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HP P2000 Array System Remote Snap Software Technical white paper Table of contents Introduction..................................................................................................................................3 HP P2000 Array System Remote Snap Software product overview ..................................................3 What‘s new? ...............................................................................................................................3 CHAP settings and Remote Snap ....................................................................................................7 Benefits of the HP P2000 Array System Remote Snap Software ..........................................................8 Disaster recovery ......................................................................................................................8 Backup ....................................................................................................................................9 Development ............................................................................................................................9 How the technology works .............................................................................................................9 The HP P2000 Array System Remote Snap Software setup requirements ........................................11 Network requirements .............................................................................................................11 The HP P2000 Array System Remote Snap Software basic functions ................................................12 Adding a remote system ..........................................................................................................13 Creating a replication set .........................................................................................................13 Deleting a replication set .........................................................................................................13 Exporting a replication image ..................................................................................................13 Setting the primary volume .......................................................................................................13 Verifying the remote link ..........................................................................................................13 Types of replications ...................................................................................................................14 Local replication .....................................................................................................................14 Remote replication ..................................................................................................................18 Disaster recovery operations ....................................................................................................19 Use cases ..................................................................................................................................20 Single office with a remote site for backup and disaster recovery using iSCSI to replicate data ........21 Single office with a local site disaster recovery and backup using iSCSI ........................................23 Single office with a local site disaster recovery and backup using FC ............................................24 Two branch offices with disaster recovery and backup ................................................................25 Single office with a target model using FC and iSCSI ports ..........................................................26 Multiple local offices with a centralized backup ..........................................................................27 Replication of application-consistent snapshots ...........................................................................28 Replication of the Microsoft VSS-based application-consistent snapshots ........................................30 Best practices .............................................................................................................................33 Fault tolerance ........................................................................................................................33 Volume size and policy............................................................................................................33 License ..................................................................................................................................34 Scheduling .............................................................................................................................34 Physical media transfer ............................................................................................................35 Replication setup wizard ..........................................................................................................35 Application-consistent snapshots ...............................................................................................35 Max volume limits ...................................................................................................................36 Monitoring .............................................................................................................................36 Performance tips .....................................................................................................................37
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HP P2000 Array System Remote Snap SoftwareTechnical white paper

Table of contents Introduction ..................................................................................................................................3 HP P2000 Array System Remote Snap Software product overview ..................................................3 Whats new? ...............................................................................................................................3 CHAP settings and Remote Snap ....................................................................................................7 Benefits of the HP P2000 Array System Remote Snap Software ..........................................................8 Disaster recovery ......................................................................................................................8 Backup ....................................................................................................................................9 Development ............................................................................................................................9 How the technology works .............................................................................................................9 The HP P2000 Array System Remote Snap Software setup requirements ........................................11 Network requirements .............................................................................................................11 The HP P2000 Array System Remote Snap Software basic functions ................................................12 Adding a remote system ..........................................................................................................13 Creating a replication set .........................................................................................................13 Deleting a replication set .........................................................................................................13 Exporting a replication image ..................................................................................................13 Setting the primary volume .......................................................................................................13 Verifying the remote link ..........................................................................................................13 Types of replications ...................................................................................................................14 Local replication .....................................................................................................................14 Remote replication ..................................................................................................................18 Disaster recovery operations ....................................................................................................19 Use cases ..................................................................................................................................20 Single office with a remote site for backup and disaster recovery using iSCSI to replicate data ........21 Single office with a local site disaster recovery and backup using iSCSI ........................................23 Single office with a local site disaster recovery and backup using FC ............................................24 Two branch offices with disaster recovery and backup ................................................................25 Single office with a target model using FC and iSCSI ports ..........................................................26 Multiple local offices with a centralized backup ..........................................................................27 Replication of application-consistent snapshots ...........................................................................28 Replication of the Microsoft VSS-based application-consistent snapshots ........................................30 Best practices .............................................................................................................................33 Fault tolerance ........................................................................................................................33 Volume size and policy............................................................................................................33 License ..................................................................................................................................34 Scheduling .............................................................................................................................34 Physical media transfer ............................................................................................................35 Replication setup wizard ..........................................................................................................35 Application-consistent snapshots ...............................................................................................35 Max volume limits ...................................................................................................................36 Monitoring .............................................................................................................................36 Performance tips .....................................................................................................................37

Troubleshooting ..........................................................................................................................37 FAQs ........................................................................................................................................38 Summary ...................................................................................................................................39 Glossary ....................................................................................................................................39 For more information...................................................................................................................41

IntroductionThis document provides information for using the HP P2000 Array System Remote Snap Software. The following topics are covered:

Benefits of the P2000 Array System Remote Snap Software How the HP P2000 Array System Remote Snap Software technology works HP P2000 Array System Remote Snap Software basic functions Types of replication Use cases Best practices Troubleshooting

HP P2000 Array System Remote Snap Software product overviewThe HP P2000 Array System Remote Snap Software has array-based functionality that provides remote replication on the HP P2000 G3 Array. The following array controllers support the HP P2000 Array System Remote Snap Software:

HP StorageWorks P2000 G3 FC Modular Smart Array Controller HP StorageWorks P2000 G3 FC/iSCSI Combo Modular Smart Array Controller HP P2000 G3 10GbE iSCSI Modular Smart Array System HP P2000 G3 iSCSI Modular Smart Array SystemNote: We do not support the remote snap feature on HP P2000 G3 SAS Modular Smart Array System

The HP P2000 Array System Remote Snap Software is a form of asynchronous replication that replicates block-level data from a volume on a local system to a volume on the same system or on a second independent system. The second system may be at the same location as the first, or it may be located at a remote site.

Whats new?This section describes new enhancements and support added to the HP P2000 G3 Modular Smart Array System with the release of the new TS230 firmware.

Remote Snap support for iSCSI controllers Concurrent Remote Snap and I/O with iSCSI controllers A new tool to check local system link Replication-set-connected port fieldRemote snap support for iSCSI controllers The controllers listed below now support the Remote Snap feature with TS230 firmware.

HP P2000 G3 iSCSI Modular Smart Array Dual Controller HP P2000 G3 10GbE iSCSI Modular Smart Array Dual Controller

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Concurrent Remote Snap and I/O with iSCSI controllers You can use iSCSI host ports for both Remote Snap and I/O with any HP P2000 G3 iSCSI arrays running TS230 firmware. We do not support both remote snap and I/O at same time using iSCSI host ports with any pre-T230 firmware. A new tool to check local system link You can check the connectivity of host ports between controllers in the local system. When you check links, the panel may show this information for each linked host port in both controllers. You can access this tool from the SMU (System Name (P2000 G3 iSCSI) > Tools > Check Local System Link) and the CLI (run command verify links)

It will check links from controller A ports to controller B ports irrespective of where you run the command from(e.g. controller A or B).

In the CLI, you can use the same command to check remote system links for the replication purposes; this tests thelinks to be used for replication from one system to another system.

In the Replication Wizard, you can also enable a local link check by selecting the check box.Screenshots below explain the different ways of using the tool (SMU, CLI etc). You can choose any one of these methods to check the connectivity. Note: Verify links can be used to check links to the remote system. Figure 1 shows an example of this command being used to check remote system link.

Figure 1: Check System Link Tool for remote system: CLI

# verify Port Type

links remote-system remote_sys_1 Links

--------------------------------------------A1 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 A2 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 A3 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 A4 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 B1 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 B2 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 B3 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 B4 iSCSI A1,A2,A3,A4,B1,B2,B3,B4 --------------------------------------------Success: Command completed successfully. #

Note: While using replication wizard, user can check the local link by enabling the check links option. Figure 2 is the screenshot of this step.

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Figure 2: Check Local System in the Replication Wizard in the SMU.

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Note: The previous screen shot showed how to check the local system links using the wizard. The following shows how to do the same using the tool.

Figure 3: Check Local System Link Tool: SMU

Note: The verify links command is used to check local link. Figure 4 shows the command line output of this command, and in this case all ports are connected.

Figure 4: Check Local System Link tool: CLI

# verify links Port Type Links --------------------------------------------A1 iSCSI B1,B2,B3,B4 A2 iSCSI B1,B2,B3,B4 A3 iSCSI B1,B2,B3,B4 A4 iSCSI B1,B2,B3,B4 --------------------------------------------Success: Command completed successfully. #

Connected port field in replication set For a remote primary or secondary volume, the Connects Ports field shows the IDs of up to two ports from another array (replication involves two arrays) in the local system that are connected to the remote system. If two ports are connected but only one is shown, this could mean that a problem is preventing half the available bandwidth from being used.

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Note: This field shows N/A for a local primary or secondary volume.

Figure 5: Connected ports displaying ports A1 and A2 as being used for replication

CHAP settings and Remote SnapIf you configure CHAP with Remote Snap, you can use CHAP to authenticate iSCSI login requests between the local system and a remote system:

Create a one-way CHAP record on each system. On the local system, the CHAP record must refer to the nodename of the remote system. On the remote system, the CHAP record must refer to the node name of the local system. Both records must use the same secret. Use the create chap-record command to create a CHAP record:# create chap-record name iqn.1991-05.com.microsoft:myhost.domain secret 0D12x

After the CHAP records are created, enable CHAP on the primary system, the secondary system, or both. To enable CHAP, use the set iscsi-parameters command: # set iscsi-parameters chap enabled

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Table: CHAP settings and corresponding behavior with HP P2000 Array System Remote Snap Software. Local system CHAP Disabled (Secret: No; CHAP record: No) CHAP Enabled (Secret: SECRET1; CHAP record: Yes) CHAP Enabled (Secret: SECRET1; CHAP record: Yes) CHAP Enabled (Secret: No; CHAP record: No) Remote system CHAP Disabled (Secret: No; CHAP record: No) CHAP Enabled (Secret: SECRET1; CHAP record: Yes) CHAP Enabled (Secret: SECRET2; CHAP record: Yes) CHAP Enabled (Secret: No; CHAP record: No) Expected behavior Remote Snap works fine. No iSCSI authentication Remote Snap works fine. Remote Snap will fail. Use the same secret for both the local and remote systems. Remote Snap will fail. Enabling CHAP without specifying a secret for an iSCSI initiator effectively blocks that initiator. Remote Snap works fine. Remote Snap will fail. Use the same secret for both the local and remote systems.

CHAP Disabled (Secret: SECRET1; CHAP record: Yes) CHAP Disabled (Secret: SECRET1; CHAP record: Yes)

CHAP Enabled (Secret: SECRET1; CHAP record: Yes) CHAP Enabled (Secret: SECRET2; CHAP record: Yes)

Note: If you are performing a local replication involving iSCSI ports, CHAP will not be used.

Benefits of the HP P2000 Array System Remote Snap SoftwareHP P2000 Array System Remote Snap Software replication is an HP-licensed feature for disaster recovery. It has been designed with a robust, fault-tolerant design that allows replication to continue in the event of some system failures involving communication, controllers, ports, hard drives (depending on the RAID configuration), or temporary power failure. The HP P2000 Array System Remote Snap Software can employ either Ethernet or Fibre Channel (FC) technology. The HP P2000 Array System Remote Snap Software technology enables the following key data management and protection capabilities:

Continuity of business systems in the event of a failure on the primary site Access to data at a remote site, for either dispersed operations, or development activities Multiple recovery points using snapshots

Disaster recoveryThe HP P2000 Array System Remote Snap Software provides access to data at a secondary site when the primary site experiences a critical failure. The HP P2000 Array System Remote Snap Software enables a maximum of 16 data volumes to be replicated to a separate offsite location. Recovery time is reduced at the primary location because data is still available at the secondary site. The data stored at the secondary site can then be used to restore the primary location once it is back online, or the data can be exported and used by users at the secondary site. A remote site should be set up to replicate the data at regular intervals. When a disaster occurs at a local site, applications can switch to the remote site. The data that was replicated from the local site can still be accessed. Minimal downtime occurs while switching the application to the remote site, and data is made available from the last replication point. Setting up the remote site and replicating data at regular intervals protects the data in the event of outages at the local site.

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BackupThe HP P2000 Array System Remote Snap Software can replicate up to 16 volumes, with up to 126 replication snapshots per volume and marginal impact on server performance. The software can be used by small businesses as a primary backup tool and by large businesses as a secondary backup tool at data centers. The HP P2000 Array System Remote Snap Software can be used as interim storage for backing up to removable media such as tape. The remote site can be as a centralized backup location for branch offices. Alternatively, remote offices can replicate to central data centers where backups occur. The software reduces the overall backup time by replicating only data that has been modified. Because the software supports either FC or Ethernet interconnects, businesses have the flexibility to use the technology that best matches their current environment.

DevelopmentThe HP P2000 Array System Remote Snap Software enables different development use cases:

An application administrator can test patches or changes in the local system by switching the applications to the

remote site. Once the testing of the patch update is completed, the administrator can switch the applications back to the local site. database volumes by exporting the snapshots on the remote system. When the exported snap shot is no longer needed, it can be deleted.

A database application development team can have access to regularly scheduled snapshots of the replicated

How the technology worksFunctionality of the P2000 family is based on the existing snapshot technology offered by the HP P2000 G3 Modular Smart Array Systems. Snapshots are used to track the data to be replicated by determining the differences in data updated on the master volume, minimizing the amount of data to be transferred. The HP P2000 Array System Remote Snap Software enables snapshots of data to reside on another array at a location other than the primary site. To perform a replication, the system takes a snapshot of the volume to be replicated, creating a point-in-time image of the data. The system replicates this point-in-time image to the destination volume by copying only the differences in the data between the current snapshot and the previous one via TCP/IP (iSCSI) or FC. The snapshot occurs at the volume level and is block-based. The software functions independently of the vdisk RAID and drive configuration, so the secondary volume in a given set may have different underlying RAID levels, drive counts, drive sizes or drive types than the primary volume, though the volume sizes must be identical. Since the software functions at the raw block-level, it has no knowledge of the volumes operating system configuration, the file system, or any data that exists on the volume. The HP P2000 Array System Remote Snap Software uses a pull model for replication. In a pull model, the secondary volume requests data from the appropriate snapshot on the primary volume. The HP P2000 Array System Remote Snap Software replication process includes the following steps: 1. Create a snapshot on the primary volume. This snapshot is a component of a replication image. 2. The local array sends a notification to the designated remote array that a replication operation has been started for a given storage volume. 3. The remote array requests a difference list from the local array. This list contains only the changed storage blocks of the primary volume since the last replication command (previous sync point snapshot). The difference list contains all storage blocks from the first replication of the primary volume. 4. The local array sends a difference list to the remote array. 5. The remote array requests all blocks in the difference list from the local array. 6. When the transfer is complete, the remote array creates a new snapshot to track newly acquired storage blocks. The remote array creates snapshots of the secondary volume for each replication.

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7. The HP P2000 Array System Remote Snap Software feature repeats step 1 and queues steps 26 for each new replication command issued to the same replication set until the prior replication command is complete. As long as the sync points are maintained, new replication commands to the same primary volume can be performed, while one or more previously executed replication commands are still in process. This enables the user to take snapshots at discrete intervals without waiting for any previous replications to complete.

Figure 6: The HP P2000 Array System Remote Snap Software creation cycle

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The HP P2000 Array System Remote Snap Software setup requirementsTo set up the HP P2000 Array System Remote Snap Software using the P2000 G3 FC Modular Smart Array System, observe the following requirements:

Two dual-controller arrays with all ports configured are required and must be connected via a switch: A direct connection between systems is not supported.

The management ports on the two P2000 G3 arrays must be on the same network when using the SMU to createreplication sets.

Remote Snap does not supported SAS. Refer to the product overview section in the introduction (page 3).Note: For more information on controller types and additional specifications, see the HP P2000 G3 Modular Smart Array QuickSpecs.

The HP P2000 Array System Remote Snap Software license must be enabled on the local and remote systems: To explore the HP P2000 Array System Remote Snap Software, enable the 60-day temporary license. To permanently enable the HP P2000 Array System Remote Snap Software, purchase a license.

The HP P2000 Array System Remote Snap Software supports up to 16 replication sets per array. If a volume on thesystem is participating in a replication set, either as a primary volume or as a secondary volume, it counts against the 16 replication set limit.

For the combo controller array, configure all of the iSCSI ports with valid IP addresses. At least one vdisk on the remote system is required to create replication set. Creating replication sets with the SMU requires adding the remote system to the local system. Creating replicationsets with the CLI is easier if the remote system is added, but is not necessary.

The primary and secondary volumes must be the same size.

Network requirementsThe following is a guideline for users setting up iSCSI controllers with T230 firmware (1 Gb and 10 Gb ports) to use remote snap feature. System or environment variables Hardware type: 10 Gb or 1 Gb Priority (set from set replication-volume-parameters priority): Low, Medium, or High Number of concurrent inbound replications (Rp) (from the primary systems view): User-configured Number of inbound channels (Cp) (from the primary systems view): User-configured Number of concurrent outbound replications (Rs) (from the secondary systems view): User-configured Number of outbound channels (Cs) (from the secondary systems view): User-configured Packet loss rate (PL): You may get this from a switch or router, or use a tool such as PathPing or mtr. Round trip time (RTT) in ms: Get this from ping Bandwidth (BW) in Kilobytes/second (Kbps): Use a bandwidth speed test available from many websites. Congestion Avoidance Loss (CAL): This is difficult to obtain. It is generally around 30% for a WAN, but higher as distance increases. Throughput requirements Data Transfer Pending (DTP) depends on the Priority: 1280 for low, 2816 for medium, or 4096 for high. Primary system calculations: Primary timeout (TOp): 30 ms Throughput required (Tp) = DTP * Rp / TOp Minimum throughput required (MTp) = 13 KB/s

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Secondary system calculations: Secondary timeout (TOs): 40 ms 1 Gb throughput required (Ts): DTP * Rs (up to 8) / TOs 10 Gb throughput required: N/A Minimum throughput required (MTs) = 9.6 KB/s Network Throughput Maximum segment size (MSS): 8960 if Jumbo frames are enabled, 1460 otherwise TCP window size (TWS) in Kilobytes: 32 KB for 1 Gb controllers, 64 KB for 10 Gb controllers Throughput limit by packet loss (Bps): If PL = 0, then 0, else MSS/ (RTT/1000) * (1/SQRT (PL)) Throughput limit by RTT (Bps): TWS/ (RTT/1000) * (1-CAL) Throughput limit by Bandwidth (Bps): BW * 1024 Network throughput limit (NTL): Minimum of throughput limit by packet loss (if non-zero), throughput limit by RTT and throughput limit by bandwidth Results Primary system throughput required to avoid timeout (TOAp) (KB/s) = Tp / Cp For the primary system

If the NTL is greater than the TOAp, the replication should not timeout. If the NTL is greater than the MTp, timeouts will occur, but the replication should succeed. If the NTL is less than the MTp, the replication will fail.Secondary system throughput required to avoid timeout (TOAs) (KB/s) = Ts / Cs for 1 Gb controllers, N/A for 10 Gb controllers. For the secondary system with 1 Gb controllers

If the NTL is greater than the TOAs, the replication should not timeout. If the NTL is greater than the MTs, timeouts will occur, but the replication should succeed. If the NTL is less than the MTs, the replication will fail. If the secondary system contains 10 Gb controllers, then thereplication should not timeout.

The HP P2000 Array System Remote Snap Software basic functionsThe following functions are highlighted in this section:

Adding a remote system Creating a replication set Deleting a replication set Exporting a replication image Setting the primary volume Verifying the remote linkFor more information on the HP P2000 Array System Remote Snap Software functions, see the HP P2000 G3 Modular Smart Array System SMU reference guide.

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Adding a remote systemThis operation adds the remote system to the local system. The remote system is listed in the navigation tree. This operation is required when using the SMU to create a replication set. This operation is not required when using the CLI, but makes it easier to create a replication set.

Creating a replication setThis operation connects the secondary volume and the primary volume. To create a replication set, specify the local and remote systems and the link type (iSCSI or FC). For the remote volume, you must first specify the system (the local system is the default), and either a remote vdisk, in which case a volume is created automatically, or a secondary volume, which must be of the same size as the primary volume. The secondary volume can reside on the local or remote system. Users can perform this operation either with the SMU or CLI. Choose your link type carefully. The link type of the replication set cannot be changed later. Also, the primary volume does not have to be created as a master volume. The process of creating the replication set converts a standard volume to a master volume. However, if a secondary volume is created, it must be created as a replication-prepared volume, using the prepare-replication-volume parameter of the create volume command in the CLI, or by checking the Replication Prepare box on the Provisioning > Create Volume page.

Deleting a replication setNot all volumes associated with the replication set are deleted, but they are automatically converted to regular master volumes and standard snapshots.

Exporting a replication imageA replication image can be exported to a standard snapshot, which can be mounted and used to verify data or for any other purpose. Any change made in this new snapshot does not affect the original replication snapshot. Snapshots exported from a replication image count against the snapshot license limits.

Setting the primary volumeBy default, the source volume is designated as a primary volume and the destination volume is designated as a secondary volume. If any failure occurs at the local site, the secondary volume on the remote system can be changed to a primary volume (the secondary volume now appears as a primary volume in the remote system). The result is that this volume now can be mapped and is accessible to the hosts. This is necessary for applications to fail over to the remote site. Once your local site comes up again, you must change the original primary volume to secondary volume for the following reasons: 1. If both the volumes participating in the replication set are primary volumes, replication will not complete. 2. Once the volume at the local system becomes secondary, the user can replicate data back from the remote system to the local system. This will synchronize the two systems. Since a secondary volume cannot be mapped, unmap a primary volume before changing it to a secondary volume. Once the data is replicated back to local system from the remote system, change the primary volume to a secondary volume by giving up its status as a primary.

Verifying the remote linkThe Tools > Check Remote System Link function of the SMU and the verify remote-link command in the CLI are available to verify the link connectivity between the local and remote systems. This tool should be run before creating a replication set. Sample outputs of check remote system link in the Modular Smart Array SMU and Modular Smart Array CLI are provided here.

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Figure 7: Check remote system link output with full connectivity

Figure 8: Check remote system link CLI output. A few FC ports are not connected.# verify remote-link remote-system Velma link-type all Port Type Remote Links ----------------------------------------------------------------------------------------- A1 A2 A3 A4 B1 B2 B3 B4 FC A2,B1 FC A1,B2

iSCSI A3,A4,B3,B4 iSCSI A3,A4,B3,B4 FC FC A2,B1 A1,B2

iSCSI A3,A4,B3,B4 iSCSI A3,A4,B3,B4

--------------------------------------------- Success: Command completed successfully. #

Types of replicationsThe HP P2000 Array System Remote Snap Software can perform both local and remote replication.

Local replicationLocal replication occurs when the primary and secondary volumes reside on the same system. Create the primary volume on one vdisk and the secondary volume on another vdisk. Then, create a replication set. Once the set is created, replications can be initiated. The following figures provide examples of the reporting of replication sets in the Modular Smart Array SMU and the Modular Smart Array CLI.

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Figure 9: Modular Smart Array SMU showing a complete setup of local replication

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Figure 10: Modular Smart Array CLI output showing a complete setup of local replication (same as above SMU illustration)# show replication-sets Replication Set [Name (rsrvd01_v001) Serial Number (00c0ffda426100489ed7904c01000000) ] Primary Volume: Name Serial Number Status Status-Reason Monitor Location Primary-Volume Primary-Volume-Status MaxQueue MaxRetryTime On Error Link Type On

Primary-Volume-Serial Collision Monitor Priority ------------------rrvd01_v001

00c0ffda4261004876d7904c01000000 Online N/A Online 32 1800

OK

Local Retry

rvd01_v001 iSCSI Oldest

00c0ffda426100484bba774c01000000 60 Medium Remot

----------------------------------------IP=16.83.136.159:3260 IP=16.83.136.160:3260 IP=16.83.136.161:3260 IP=16.83.136.162:3260 rvd01_v001 00c0ffda426100484bba774c01000000 Online N/A Online 32 1800 OK Local Retry rvd01_v001 iSCSI Oldest 60

00c0ffda426100484bba774c01000000 Medium Remot

----------------------------------------IP=16.83.136.159:3260 IP=16.83.136.160:3260 IP=16.83.136.161:3260 IP=16.83.136.162:3260 Success: Command completed successfully. # show replication-images rsrvd01_v001 Volume Summary [Name (rrvd01_v001) Serial Number (00c0ffda4261004876d7904c01000000) Type (Secondary Volume) ] Images: Image Serial Number -----------------00c0ffda42610048e3d7904c01000000 rvd01_v001_i01 Status Progress Start Date/Time 00c0ffda4261004881d8904c01000000 Snap12845610250 Suspended Est Complete 2010-09-15 14:30:29 Time Image Name Snapshot Serial Snapshot Name Creation Date/Time

Last Update

----------------------------Complete N/A 2010-09-15 14:27:47 2010-09-15 14:30:29 N/A N/A 00:02:42 2010-09-15 15:20:24 Time

00c0ffda4261004836e4904c01000000 rvd01_v001_i02 Status Progress Start Date/Time

00c0ffda4261004837e4904c01000000 Snap12845640230 Suspended Est Complete

Last Update

---------------------------------------------------------------------------------------------------------------------------------------------Complete N/A 2010-09-15 15:20:23 2010-09-15 15:20:24 N/A N/A 00:00:01

Volume Summary [Name (rvd01_v001) Serial Number (00c0ffda426100484bba774c01000000) Type (Primary Volume) ] Images: Image Serial Number ----------------00c0ffda42610048e3d7904c01000000 rvd01_v001_i01 00c0ffda4261004836e4904c01000000 rvd01_v001_i02 Success: Command completed successfully. 00c0ffda42610048ced7904c01000000 rvd01_v001_i01 00c0ffda426100482de4904c01000000 rvd01_v001_i02 2010-09-15 14:27:26 2010-09-15 15:20:13 Image Name Snapshot Serial Snapshot Name Creation Date/Time

We recommend performing an initial local replication before performing a remote replication as part of a disaster recovery setup or backup. If there is a huge amount of data in the primary volume during the initial remote replication, it can take a long time to complete and can cause bandwidth congestion. In order to avoid congestion, the user can do a local replication and then transfer the secondary volume to the remote system (physical media transfer). Once the initial replication is completed, perform a physical media transfer to move the secondary volume to the remote site. The initial replication between a primary volume and a secondary volume requires a full data copy between the two volumes. Since the initial replication is a full data copy, every block on the volume is copied. This can take a significant amount of time depending on the amount of data and the link between the primary and remote sites. See Figure 6 for an illustration of local replication and physical media transfer.

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Figure 11: Illustration of local replication and physical media transfer

Physical media transfer Once the first replication is completed, do the following: 1. Detach the secondary volume (outlined in next section), which resides on the local system. If the secondary volumes vdisk contains any other secondary volumes, detach those volumes also. 2. First, make sure the detach operation is completed. Stop the secondary volumes vdisk using the stop vdisk command in CLI or using vdisk > Provisioning > Stop vdisk function in SMU. If the secondary volume or volumes snap pools are on other vdisks, stop those vdisks also. 3. Remove the disks or enclosure containing the disks and move them into the remote system. 4. At the remote site, insert the disks or attach the enclosure to the remote system. HP recommend powering down an enclosure before inserting disks. Make sure that the remote system supports the chosen link type (iSCSI or FC); the link type cant be changed once the replication set has been created. 5. Start the snap pools vdisks using the start vdisk command in CLI or vdisk > Provisioning > Start vdisk function in the SMU (only if the secondary volumes snap pools are in a different vdisk). 6. Start the secondary volumes vdisks. The secondary volume appears on the system at the remote site. You will need to reattach the secondary volume to add it to the set. This operation makes the secondary volume a part of the original set. 7. Continue replicating from the local site.

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Detaching a replication volume

You must detach the replication volume before moving the secondary volume to the remote system. Make sure the initial replication is completed before detaching the secondary volume. Once the secondary volumeis detached it remains part of the replication set but is not updated with any new data.

After detaching the secondary volume stop the secondary volumes vdisk and associated snap pools vdisk (if thesecondary volume and its snap pool reside on a separate vdisks) before moving the disks to remote system.

If you intend to move the disk drive enclosure, add this enclosure at the end of the chain of connected enclosures.

Before removing the drive enclosure from the system, power off the enclosure. But if you are removing only the disks there is no need to power off the enclosure. After the drive enclosure is powered off, there will be unwritable cache data in the drive enclosure. Use the clear cache command in the CLI to clear the unwritable cache. Use the detach replication-volume command via the CLI or using the SMU: Provisioning > Detach Replication Volume.

Reattaching a replication volume

After the secondary volume and its snap pool are moved to the remote system, start the vdisk(s) and reattach it

using the reattach replication volume command or the Provisioning > Reattach Replication Volume page in the SMU. After the volume is reattached, the replication set can resume replication operations. volume resides on one of the following:

Users can perform the physical media transfer by setting up a local replication in such a way that the secondary On the same array but on different vdisks (so that disks can be removed and physically transferred to the remote site). In an attached Modular Smart Array drive enclosure. This drive enclosure will be attached to a remote system later.

Remote replicationFor an illustration of remote replication usage for initialization of the remote site, see Figure 12.

Figure 12: Replication initialization options

Using FC Users can set up local and remote sites connected via an FC network and can have replication sets performing replications over FC. This is useful in cases where local and remote sites are in different blocks of a campus or building.

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FC ports can be used to transfer regular data while they are being used for replication. However, this action will result in decreased performance for both the data path and the replication transfer. Using iSCSI When the local and remote systems are in different geographical regions, users can create replication sets using iSCSI to perform replications over WAN. For example, when the local system is in New York and you are planning to set up your backup system (remote system) in Houston, you can create remote replication sets using iSCSI as the transfer media for performing replications. Perform a physical media transfer to overcome bandwidth and latency issues with the initial replication. These issues can sometimes be caused by a large amount of data in the primary volume getting replicated to a remote system. (See more on these issues in the Physical media transfer section above). If user is running firmware older than T230, host I/O and replication should not be done at the same time on an iSCSI port.

Disaster recovery operationsIf the local site fails, the applications need to switch to the remote site. To bring up the remote site, do the following: 1. Convert the remote volume (secondary volume) to a primary volume using the set replication-primaryvolume CLI command or by selecting Provisioning > Set Replication Primary Volume from the SMU. o During the conversion to a primary volume, the volume is rolled back, or synced, to a replication snapshot. By default, the volume syncs to the latest replication snapshot, but you can choose any of the previous replication snapshots. Any data that has not been replicated is lost. A secondary volume can be converted to a primary via the SMU or CLI.

o o

2. The new primary volume, which resides on the remote site, can be mapped to a LUN and used as you would use the original volume. 3. Switch the applications to this primary volume and continue using the application. Once the failure has been addressed at the local site, complete the following steps: 1. Make the original primary volume a secondary volume using the set replication-primary-volume CLI command or by selecting Provisioning > Set Replication Primary Volume from the SMU.

Important: A secondary volume cannot be mapped, so be sure to unmap the primary volume before attempting to make it a secondary volume.

2. Replicate any data written to the remote volume (now acting as primary volume residing at remote system) to this volume residing at local system (now acting as secondary volume). This can be performed in a single replication or in multiple replications. This ensures that all data has been transferred properly. 3. After all the data is replicated back to the local site, convert the volume at the local site to the primary volume and then convert the remote volume to the secondary volume. To convert a primary volume to a secondary volume, set the other volume of the replication set as the primaryperform this operation on both systems. The user can perform this operation using the CLI command set replication-primary-volume or using the SMU via Primary Volume > Provisioning > Set Replication Primary Volume function. For the HP P2000 G3 SMU screen shot details, see the HP P2000 Remote Snap Technical Cookbook. 4. Re-establish the replication set to the remote site. Continue using the scheduler for running remote replications in regular intervals.

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Figure 13: Disaster recovery operations

Use casesThis white paper provides examples that demonstrate the HP P2000 Array System Remote Snap Softwares ability to replicate data in various situations.

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Single office with a remote site for backup and disaster recovery using iSCSI to replicate dataFigure 14: Single office with a remote site for backup and disaster recovery (iSCSI)

Figure 15: Single office with a remote site for backup and disaster recovery (iSCSI) CLI output# create vdisk level raid5 disks 1.1,1.2,1.3 vd01 Success: Command completed successfully. (vd01) - The vdisk was created. # create snap-pool size 10GB vdisk vd01 sp1 Success: Command completed successfully. (sp1) - The snap pool was created. # create master-volume snap-pool sp1 size 20GB vdisk vd01 FSDATA Success: Command completed successfully. (FSDATA) - The master volume was created. # create remote-system username manage password !manage 16.83.138.215 Success: Command completed successfully. (16.83.138.215) - The remote system was created. # create replication-set remote-system 16.83.138.215 remote-vdisk remote-vd01 link-type iSCSI FSDATA Info: Verifying that the secondary volume was added. This may take a couple of minutes... Info: The secondary volume was created. (rFSDATA) Info: The primary volume was prepared for replication. (FSDATA) Info: Started adding the secondary volume. (rFSDATA) Info: Added secondary volume rFSDATA. (rFSDATA) Success: Command completed successfully. (FSDATA) - The primary volume is ready for replication. # # replicate volume FSDATA snapshot image-1 Success: Command completed successfully. (00c0ffdaff130000b439bc4c01000000) - Initiated replication of volume image-1.

To configure a single office with a remote site for backup and disaster recovery (iSCSI): 1. Set up a P2000 G3 hybrid array with enough disks (according to the application load and users), then configure the management ports and iSCSI ports with IP addresses. Install the HP P2000 Array System Remote Snap Software license if one has been purchased, or install the temporary license from the Tools > Install License page of the SMU. 2. Create master volumes FS Data and App A Data, enabling snapshots. Snap pools are automatically created with the default policy and size, or you can adjust the settings as necessary. Make sure the volumes are in different vdisks and that each vdisk has enough space to expand the snap pool in the future.

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3. Connect your array to the WAN. If using iSCSI over the WAN as part of your disaster recovery solution, connect your file server and application server to the WAN. Connecting the management port of an array to the WAN helps you to manage the array remotely and is necessary when using the SMU to create the replication sets. 4. Map the volumes to the file server and the application server. 5. Identify a remote location and set up a second P2000 G3 array and configure both the management ports and the iSCSI ports. This is the remote system. Configure the vdisks to accommodate destination volumes at a later stage. 6. In both the local system and the remote system, add the other system using the Configuration > Remote Systems > Add Remote System page of the SMU. 7. Verify the data path between your local system and remote system using the Tools > Verify Remote Link. Always configure all four iSCSI ports to facilitate a working connection to the WAN. 8. Set up the replication sets for the volumes FS Data and APP A Data using the replication wizard, and choose iSCSI as the link type. 9. After the setup is complete, schedule the replication in desired intervals, based on the application load, critical data, replication window (the time it takes to perform a replication) and so on. This enables you to have a complete backup and disaster recovery setup. 10. Verify the progress of replications by checking the replication images. It lists the progress or completed message. 11. Verify the data at the remote location by exporting the replication image to a snapshot and mounting it to a host. 12. In case of a failure at the local site, it is possible to switch the application to the remote site. Do the following:

Move the remote Modular Smart Array to the local site. Move disks that contain the destination volume to the local site. Replace the local Modular Smart Array with the new Modular Smart Array, and then replicate the data. Use the iSCSI target mode to provide the host access for the file server and application server to access theremote site.

For more information on disaster recovery, see Disaster recovery operations on page 19.

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Single office with a local site disaster recovery and backup using iSCSIFigure 16: Single office with a local site disaster recovery and backup using iSCSI

To configure a single office with a local site disaster recovery and backup using iSCSI: 1. Set up two HP P2000 G3 combo arrays at the local site. 2. Connect the file servers and application servers to the arrays via an FC SAN. 3. Mount the volumes to the applications. 4. Create multiple replication sets with FS Data and App A Data as primary volumes to the second HP P2000 G3 system. On the second system, create the App B volume, map it to the hosts, and use it as the source of a replication set with the first system as the destination. These replication sets are created using the iSCSI link type. We recommend that both of the HP P2000 G3 systems are connected by a dedicated Ethernet link (LAN). 5. Switch the applications to the other system if any failures occur on either of the two systems.

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Single office with a local site disaster recovery and backup using FCFigure 17: Single office with a local site disaster recovery and backup using FC

To configure a single office with a local site disaster recovery and backup using FC: 1. Set up two HP P2000 G3 combo arrays at the local site. You can also use the HP P2000 G3 FC controllers. 2. Connect the file servers and application to these arrays via an FC SAN. 3. Mount the volumes to the applications. 4. Create multiple replication sets with FS Data and App A Data as primary volumes to the second HP P2000 G3 system. On the second system, create the App B volume, map it to the hosts, and use it as the source of a replication set using the first system as the destination. These sets are created using the FC link type. 5. Switch the applications to the other system if any failures occur on either of the two systems.

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Two branch offices with disaster recovery and backupFigure 18: Two branch offices with disaster recovery and backup

To configure two branch offices with disaster recovery and backup: 1. Set up an HP P2000 G3 hybrid array with enough disks (according to the application load and users) and configure the management ports and iSCSI ports with IP addresses. Install the HP P2000 Array System Remote Snap Software license, if one has been purchased, or install the temporary license from the Tools > Install License page of the SMU. 2. Create the master volumes FS Data and App A Data in the array, enabling snapshots. Snap pools are automatically created with the default policy and size, or you can adjust the settings as necessary. Make sure volumes are in different vdisks and that each vdisk has enough space to expand the snap pool in the future. 3. Connect your array to the WAN. If using iSCSI over the WAN as part of your disaster recovery solution, connect your file server and application server to the WAN. Connecting the management port of the array to the WAN helps you to manage the array remotely and is necessary when using the SMU to create the replication sets. 4. Map the volumes to the file server and application server. 5. Identify a remote location and set up a second HP P2000 G3 array and configure both management ports and iSCSI ports. This is your remote system. Configure the vdisks to accommodate destination volumes at a later stage. 6. At the local site, create remote replication sets using the master volumes FS A and App A. Corresponding destination volumes are created automatically in the remote site. 7. Schedule replications at regular intervals. This ensures that data at the local site is backed up to the remote site. 8. Set up remote replications at the remote site for volumes FS B and App B. Destination volumes are created at the local site. 9. Schedule replications at regular intervals so that all data at the remote site is backed up to the local site. In case of failure at either the local site or the remote site, you can fail over the application to the available site.

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Single office with a target model using FC and iSCSI portsFigure 19: Single office with target model using FC and iSCSI ports

To configure a single office with a target model using FC and iSCSI ports: 1. Set up an HP P2000 G3 hybrid array with enough disks, according to the application load and number of users, and configure the management ports and iSCSI ports with IP addresses. 2. Create master volumes App A Data, App B Data, and FS Data in the array, enabling snapshots. Snap pools are automatically created with the default policy and size, or you can adjust the settings as necessary. Make sure volumes are in different vdisks and that each vdisk has enough space to expand the snap pool in the future. 3. Map FS Data to the iSCSI port so that the file server can use this volume via the iSCSI interface. 4. Map App A Data and App B Data volumes to the FC port so that the application servers can access these volumes via the FC SAN. Using the HP P2000 G3 hybrid controllers provides several advantages:

You can leverage both the FC and iSCSI ports for target-mode operations You connect file servers and other application servers that are not part of the FC SAN to the array using the iSCSIports via the LAN or WAN

You can connect new servers with FC connectivity directly through the FC SANNote: Accessing a volume through both iSCSI and FC is not supported.

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Multiple local offices with a centralized backupFigure 20: Multiple local offices with a centralized backup

1. Setup P2000 G3 combo controller system with enough disks and configure the iSCSI ports with valid IP addresses. Install the software license at remote sites A, B, and C. 2. Create volumes (master volumes) FS A Data and App A Data corresponding to file server and application server (accessing these volumes) at remote sites. 3. Setup an HP P2000 G3 system at the centralized location and make sure that it has enough disks to accommodate data coming from remote sites A, B, and C and install the HP P2000 Array System Remote Snap Software license. 4. Connect sites A, B, and C with the central site using the WAN and make sure iSCSI ports are configured and connected to this WAN. 5. Make sure the iSCSI ports of the HP P2000 G3 arrays at site A, B, and C can access the iSCSI ports of the HP P2000 G3 system at the central site. 6. Create replication sets for volumes FS A data and App A Data, specifying the remote central system as remote systems so that secondary volumes will be created at the central site. 7. Repeat step 8 for site B and C. 8. Schedule the replication in regular intervals so that data from site A, B, and C will get replicated to the central site.

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Replication of application-consistent snapshotsUsers can replicate application-consistent snapshots on a local Modular Smart Array HP P2000 G3 array to a remote Modular Smart Array HP P2000 G3 array. Use the Modular Smart Array SMU for manual operation and the Modular Smart Array CLI for scripted operation. Both options require you to establish a mechanism that enables all application I/O to be suspended and resumed (quiesced). Many applications enable this via a scripting method. For an illustration of the following steps, see Figure 21. To create application-consistent snapshots for any supported OS and any application: 1. Create a Modular Smart Array volume for each required application volume. When defining the volume names, use a string name variant that will help identify the volumes as a larger managed group: With the Modular Smart Array SMU: a) Use the Provisioning Wizard to create the necessary vdisks and volumes. With the Modular Smart Array CLI: b) Use the create vdisk command. c) Use the create master-volume command. 2. Create a replication set for each Modular Smart Array volume used by the application. a) Use a string name variant when defining the replication set name. This helps identify each replication set as part of a larger managed group. b) With the Modular Smart Array SMU: i. Use the Replication Wizard for each volume defined in step 1 c) With the Modular Smart Array CLI: ii. Use the create replication-set command as follows:create replication-set parm1 parm2 parmN

3. When the application and its volumes are in a quiesced state, you can create I/O-consistent snapshots across all volumes at same time. a) With the Modular Smart Array SMU, use the Create Multiple Snapshots operation. The Modular Smart Array SMU also enables scheduling snapshots one master volume at a time. For applicationconsistent snapshots across multiple Master Volumes, we recommend a server-based scheduling as explained in step 4. 4. For an automated solution, schedule scripts on the application server that coordinate the quiescing of I/O, invoking of the Modular Smart Array CLI snapshot commands, and resuming I/O. Verify that you defined the desired snapshot retention count. See the Figure 21 below for an example the Modular Smart Array CLI snapshot commands. a) With the Modular Smart Array CLI: i. Use the create snapshots command as follows create snapshots parm1 parm2 parmN The time interval between these snapshot groups will be utilized in the following steps.

Note: To achieve application-consistent snapshots, you must ensure application I/O to all volumes at the server level is suspended, prior to taking snapshots, and then resumed after the Modular Smart Array snapshot commands are taken. The P2000 Array System management firmware will only create point-in-time consistent snapshots of indicated volumes.

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Figure 21: Setup steps for replication of application-consistent snapshots

#

To replicate application-consistent snapshots: 1. Ensure all volumes have established reoccurring snapshots as detailed above. 2. Schedule each replication set. See Figure 17 for an example of Modular Smart Array CLI replication commands. a) With the Modular Smart Array SMU do the following: i. After the Replication Wizard creates the replication set, you will be prompted to select initiate replication now or schedule replication. Select the schedule option. ii. In the Scheduler screen, with Replication Mode, select Replicate Most Recent Snapshot so that the latest primary volume snapshot will be used.

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b) With the Modular Smart Array CLI do the following: i. Use the create task replicate-volume command as follows create task replicate-volume parm1 parm2 parmN ii. Use the create scheduler command as follows create scheduler parm1 parm2 parmN 3. Ensure the reoccurring schedule for each replication set coordinates with the scheduled snapshots. a) Calculate an appropriate time that falls between the application volumes snapshot times created in step 4. b) For an example of snapshot scheduling and Modular Smart Array replication scheduling, see Best practices on page 29. Create your own naming scheme to manage your application data volumes, snapshot volumes, and replication sets. In your naming scheme, include the ability to establish a recognizable grouping of multiple Modular Smart Array replication sets. This will help with managing the instances of your application-consistent snapshots and the application-consistent replication sets when restore or export operations are used.

Figure 22: Examples of using the Modular Smart Array CLI for replication of application-consistent snapshots# create snapshots volumes FSDATA,APPDATA,LOG fs1-snap,app1-snap,log1-snap Success: Command completed successfully. (fs1-snap,app1-snap,log1-snap) - Snapshot(s) were created. # show snapshots

vdisk Serial Number Name Creation Date/Time Status Status-Reason Type ------------------------------------------------------------------------------------------------------------------------vd02 00c0ffda03590048c6fec54b01000000 app1-snap 2010-04-14 17:43:34 Available N/A vd03 00c0ffda42160048c6fec54b02000000 log1-snap 2010-04-14 17:43:34 Available N/A vd01 00c0ffda42160048c6fec54b01000000 fs1-snap 2010-04-14 17:43:34 Available N/A ------------------------------------------------------------------------------------------------------------------------Success: Command completed successfully.

# replicate snapshot name repapp1 app1-snap Success: Command completed successfully. (00c0ffda03590048c6fec54b01000000) - Initiated replication of snapshot app1-snap.

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Replication of the Microsoft VSS-based application-consistent snapshotsUsers can replicate the Microsoft VSS-based application-consistent snapshots on a local HP P2000 Modular Smart Array to a remote HP P2000 Modular Smart Array. To create application-consistent snapshots using VSS: 1. Create the Modular Smart Array volumes for your application: a) When defining the volume names, use a string name variant that helps identify the volumes as a larger-managed group. b) With the Modular Smart Array SMU, use the Provisioning Wizard to create the necessary vdisks and volumes. c) With the Modular Smart Array CLI: i. Use the create vdisk command. ii. Use the create master-volume command. d) With a VDS client tool, refer to the vendor documentation to create the necessary volumes. 2. Create a replication set for each Modular Smart Array volume in the application. a) When defining the replication set name, use a string name variant that will help identify each replication set as part of a larger managed group. b) With the Modular Smart Array SMU: i. Use the Replication Wizard for each volume defined in step 1.

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c) With the Modular Smart Array CLI: i. Use the create replication command as follows: create replication-set parm1 parm2 parmN 3. Determine an appropriate Microsoft VSS backup application, or VSS requestor, that is certified to manage your VSS-compliant application. a) The HP P2000 G3 VSS hardware provider is compatible with Microsoft Windows certified backup applications. b) For a general scripted solution, see the Microsoft VSS documents for usage of the Windows Server DiskShadow (Windows 2008 and later) or VShadow (applicable for Windows 2003 and beyond) tools. 4. Configure your VSS backup application to perform VSS snapshots for all of your applications volumes. The VSS backup application uses the Microsoft VSS framework for managed coordination of quiescence of VSS-compatible applications and the creation of Modular Smart Array volume snapshots through the Modular Smart Array VSS hardware provider. a) Establish a reoccurring snapshot schedule with your VSS backup application. b) The time interval between these snapshot groups will be used in the following steps.

Note: The VSS framework, the VSS Backup application (requestor), the VSS-compliant Application writer, and the Modular Smart Array VSS hardware provider achieve application-consistent snapshots. The HP P2000 Array System firmware management features only create point-in-time snapshots of indicated volumes.

To replicate VSS-generated, application-consistent snapshots: 1. Ensure all volumes have established reoccurring snapshots as detailed above. 2. Schedule each replication set. a) With the Modular Smart Array SMU do the following: i. After the Replication Wizard creates the replication set, you will be prompted to select initiate replication now or schedule replication. Select the schedule option. ii. In the Scheduler screen, with Replication Mode, select Replicate Most Recent Snapshot so that the latest source volume snapshot will be used. b) With the Modular Smart Array CLI: i. Use the create task replicate-volume command as follows Create task replicate-volume parm1 parm2 parmN ii. Use the create scheduler command as follows create scheduler parm1 parm2 parmN 3. Ensure the reoccurring schedule for each replication set coordinates with the scheduled snapshots. Calculate an appropriate time that falls between the application volumes snapshot times as created in step 4. For an example of such VSS snapshot scheduling and Modular Smart Array replication scheduling, see Best practices on page 33.

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Figure 23: Setup steps for replication of the VSS-based application-consistent snapshots

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Best practicesFault toleranceTo achieve fault tolerance for HP P2000 Array System Remote Snap Software setup, we recommend the following:

For FC and iSCSI replications, the ports must be connected to at least one switch, but for excellent protection it is

recommended that half of the ports be connected to one switch (for example, the first port on each controller) and half of the ports be connected to a second switch, with both switches connected to a single SAN. This avoids having a single point of failure in the switch. Direct Attach configurations are not supported by replication over FC and iSCSI. The iSCSI ports must all be routable on a single network space.

In case of link failure, the replication operation will re-initiate within a specified amount of time. The amount of time

is defined by the parameter max-retry time (the default value is 1800 seconds). Set this time to a preferred value according to your setup. Once the retry time has passed, replication goes into a suspended state and then needs user intervention to resume. either 0 (retry forever) or 60 minutes for every 10 GB in volume size to prevent a replication set from suspending when multiple errors occur. This can be done in the CLI by issuing the following command:

During a single replication, we recommend setting the maximum replication retry time on the secondary volume to

set replication-volume-parameter max-retry-time

Replication services are supported on both single-controller and dual-controller environments, but only between

similar environments. That is, a single-controller system can replicate to a single-controller system or a dualcontroller system can replicate to a dual-controller system. Replication between a single-controller system and a dual-controller system is not supported. replication continues through the second controller.

We recommend using a dual-controller array to try to avoid a failure of one controller. If one controller fails,

Volume size and policy While setting up the master volumes, keep note of the size of the vdisk and the primary/secondary volume.Once part of a replication set, the sizes of the primary/secondary volume cannot be changed.

Every master volume must have a snap pool associated with it. If no space exists on the primary volumes

virtual disk to create the snap pool, or insufficient space is available to create or maintain a sufficiently large snap pool for the snapshots to be retained, the snap pool should be created on a separate vdisk that does have sufficient space.

To help you accurately set a snap pools size, consider the following: a. What is the master volume size, and how much will the master volume data change between snapshots? The amount of space needed by a snap shot in a snap pool depends on how much data is changed in the master volume and the interval in which snapshots are taken. The longer the interval, the more data will be written to the snap pool. b. How many snapshots will be retained? The more snapshots retained, the more space is occupied in the snap pool. c. How many snapshots will be modified? Regular snapshots mounted with read/write will add more data to snap pool. d. How much modified (write) data will the snapshots have? The more data is modified for mounted snapshots, the more space is occupied in the snap pool.

Although the firmware allows for more, it is recommended that no more than four volumes (master volume orsnap pools) be created on a single vdisk when used for snapshots or replication.

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If snap pools are considered highly critical, then the snap pool should be created on a fault-tolerant virtual disk

(for example RAID 6), and if its not considered critical the user can choose a virtual disk with no fault tolerance (for example RAID 0). the snap pool size to the desired value. By default, the snap pool policy is set to automatically expand when it reaches a threshold value of 90%. Note that the expansion of a snap pool may take up the entire volume or vdisk, limiting the ability to put additional data on that vdisk. We recommend that you set the auto expand size to a preferred value so that snap pools are not expanded too often. It is also important that you monitor the threshold errors and ensure that you have free space to grow the snap pool as more data is retained. policy. When a snapshot is deleted, all data uniquely associated with that snapshot is deleted and associated space in the snap pool is freed for use. In order to accommodate the number of volumes per vdisk limit delete unnecessary snapshots.

By default, a snap pool is created with a size equal to 20% of the volume size. An option is available to expand

Snapshots can be manually deleted when they are no longer needed or automatically deleted through a snap pool

License Use a temporary license to enable the HP P2000 Array System Remote Snap Software and get a hands-onexperience. For live disaster recovery setups, we recommend upgrading to a permanent license. A temporary license expires after 60 days, disabling further replications. replications with live systems. remote and source systems.

With a temporary license, users can test local replications and gain experience before setting up remote To set up remote replication, you must have an HP P2000 Array System Remote Snap Software license for both the Updating to a permanent license at a later stage preserves the old replication images. By default, there are 64 snapshots that can be upgraded to a maximum number of 512 snapshots. Exporting a replication image to a standard snapshot uses a license count, so be sure to install a license that allowsfor the appropriate number of snapshots.

Scheduling The scheduler can be used to replicate data from a primary volume in regular intervals to the remote system. In order to ensure that replication schedules are successful, we recommend users to schedule no more thanthree volumes to start replicating simultaneously, although as many as 16 can replicate at the same time. These and other replications should not be scheduled to start or recur less than one hour apart. If you schedule replications more frequently, some scheduled replications may not have time to start. or when using any other tool such as Microsoft VSS and you want to replicate these snapshots. This helps in achieving application-consistent snapshots.

The use existing snapshot option can be used when standard snapshots are manually taken of the primary volume

When older replication images are deleted to accommodate new replication images (based on retention count atthe local system), corresponding replication images at the secondary volume are retained, until the total volume count reaches the maximum volume limit per vdisk. maximum value of 32.

Users can set the replication image retention count to a preferred value. A best practice is to set the count to a Schedules may only be associated with the primary volume. You can see the status of a scheduler by selecting aschedule from the overview panel.

Users can modify an existing schedule to change any of the parameters such as interval time and retention count. When standard snapshots are taken at the primary volume in regular intervals (manually or using VSS), select theproper time interval for the replication scheduler so that the latest snapshot is always replicated to the remote system. The system restricts the minimum time interval between replications to 30 minutes.

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The following diagram provides a summary example.

Figure 24: Tabulation of resources used with replication of application-consistent snapshots

)

Physical media transfer Power down the enclosure or shut down the controllers before inserting the disks at the remote system and prior toreattaching the volume.

With stop and start operations for the vdisks, you dont need to power down the local system to remove disks whileperforming physical media transfer.

While performing physical media transfer, its easier to have the snap pool of the secondary volume on the samevdisk as the secondary volume. If the snap pool is on a different vdisk, you should first detach the secondary volume and stop the vdisk containing the secondary volume before stopping the vdisk with the snap pool.

Before moving the disks to a new system, ensure that the remote system does not have volumes or vdisks with the

same names as volumes on the newly inserted disks. After performing the transfer, the system should be checked for volumes and vdisks with the same names. These should be renamed before performing any other operation on the volumes.

Always check whether the initial replication is completed before detaching the secondary volume from thereplication set.

After reattaching the secondary volume, initiate a replication from the primary volume to continue syncing the databetween the local and remote systems.

Replication setup wizard The replication setup wizard helps set up remote or local replication sets. Enable Check Links when performingremote replication. This will validate the links between the local and remote systems.

When prompted, manually initiate or schedule the replication after the setup wizard is completed.

Application-consistent snapshots When snapshots are taken manually, no I/O quiescing is done at the array level. Use the create multiple snapshots command to take time-consistent snapshots across multiple volumes. Use the replication scheduler to initiate the replication of these snapshots. Select the option use existing snapshot. Software such as the Microsoft VSS framework enables quiescing applications and taking application-consistentsnapshots.

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Max volume limits Replication images can decrease the volume count per vdisk. We recommend monitoring the number ofreplication images created.

Users can restrict the number of replication images at the local system, where the primary volume is residing, by

using the retention count in the scheduler. Set it to a higher value (the maximum is 32). This limit does not apply to remote systems.

At the remote system, delete older replication images as needed. Older replication images are deletedautomatically once the volume count of the vdisk reaches the maximum volume limit.

Users take snapshots of up to 16 volumes at a single operation by using the creating multiplesnapshot command.

A vdisk can accommodate only 128 volumes, including the replication images in that vdisk.

Figure 25: Configuration limits

MonitoringReplication Users can monitor the progress of an ongoing replication by selecting the replication image listed in the navigation tree. The right panel displays the status and percentage of progress. When the replication is completed, the status appears as Completed. Events When monitoring the progress of ongoing replication, view the event log for the following events:

HP P2000 Remote Snap Software license expiredThis indicates that the temporary license has expired. The HP

P2000 Array System Remote Snap Software will no longer be available until a permanent license is installed. All the replication data will be preserved even after the license has expired, but you cannot create a new replication set or perform more replications.

Snap pool thresholdThe snap pool can fill up when there is steady I/O and replication snapshots are taken atregular intervals. When a warning event occurs, take action: either remove the older snapshots or expand the vdisk. initiated is queued. Once the problem is identified and fixed, you can manually resume the replications.

Replication suspendedIf the ongoing replication is suspended, an event is received. Any further replicationFor more related events, see the HP P2000 G3 Modular Smart Array System Event Descriptions Reference Guide. SNMP traps and email (SMTP) notifications You can set up the array to send SNMP traps and email notifications for the events described above. Using the SMU, use the Configuration > Services > SNMP Notification or Configuration > Services > Email Notification pages. For the CLI, use the set snmp-parameters and set email-parameters commands.

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Performance tipsFor a gain in replication and host I/O performance of up to 20 percent, enable jumbo frames on all infrastructure components (if supported by all) in the path and on iSCSI controllers. Jumbo frames are disabled by default for the iSCSI host ports. You can enable them using either the SMU or CLI.

Note: If your infrastructure does not support jumbo frames, enabling them only on your controllers may actually lower performance or even prevent the creation of replication sets or replications.

With the SMU, enable jumbo frames by going to (P2000 G3 iSCSI) > Configuration > System Settings > Host Interfaces With the CLI, enable jumbo frames by using the command set iscsi-parameters jumbo-frames enabled

TroubleshootingIssue: Replication enters a suspended state Recommended actions: If performing a local replication, ensure all the ports are configured and connected via the switch. Check the HP P2000 Array System Remote Snap Software license status at the local and remote site. If you are running a temporary license, the license may have expired. Install a permanent license and manually resume replication. The connectivity link may be broken. Use the Verify remote link tool to check the link connectivity between the local and remote systems. Repair the link and make sure all links are available between the systems, then manually resume the replication. Issue: You cannot perform an action such as changing the external view for a replication set Recommended actions: Actions performed on a replication set, such as schedule creation or modification and adding or removing a secondary volume, must be performed on the system where the primary volume resides. Changing the primary volume is a coordinated effort between the local and remote systems. It must first be performed on the remote system, and then on the local system. To help remember this, the secondary volume pulls data from the primary volume. To avoid a potential conflict, do not attempt to have two secondary volumes. Since the secondary volume cannot be mapped to the hosts, unmap a primary volume before converting it to a secondary volume. Issue: You cant delete a replication set involving a secondary volume Recommended actions: Convert the secondary volume to a primary volume. You can now delete the replication set.

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FAQs1. Do we support port failover? Answer: Yes. See examples below to understand how it works. Example Where the primary volume is owned by controller A and ports A1 and A2 are connected is part of the replication set (considering it as a dual-port controller)

If port A1 fails, replication will go through A2 without any issues. If port A1 and A2 fail, the replication will continue using the B1 and B2 ports of controller B (must have B1 and B2ports added to the replication set). 2. Do we support load balancing with multiple replications in progress? Answer: Yes. Example Four primary volumes owned by controller A and both ports (A1 and A2) are connected and used for replication.

All four sets will try to use both ports A1 and A2, unless the array doesnt have sufficient resources to use both ports.3. Can CHAP be added to a replication set at any time after it is created? For instance, if you have a local set for doing an initial replication and then media transfer, do you need to set up CHAP before the set creation? Answer: CHAP is specific to a system and not specific to the replication set. CHAP is specific to the local-to-remote system communication path and vice versa. Once you are done with the initial replication and physical media transfer, you can enable CHAP before reattaching the secondary volume from the remote system; the reattach operation should go through fine. 4. Does using CHAP affect replication performance? Answer: CHAP is just for initial authentication across nodes. Once a login is successful with another system, CHAP will not be involved in further data transfer, so replication performance should not be affected. 5. I created a master volume as the primary and did a local replication. Can I now do a remote replication with the same primary volume? Answer: A volume can only be part of one replication set. So, you need to delete the set and create a new set or remove the secondary volume from the set and add the other remote secondary volume to the set. 6. I initiated a remote replication, and now I am not getting an option to suspend the replication/abort the replication in the local system. Answer: By design, suspend and abort operations can only be performed on the secondary volume. You can access the secondary volume on the remote system; it has an option to suspend/resume replication. 7. I deleted the replication set using remove replication and all my replication images disappeared. Answer: All the replication images are converted to standard snapshots and can be viewed under the volume in the Snapshots section.

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8. I see an option called Enable Snapshot when attempting to create a volume. Answer: By selecting the box Enable Snapshot, you automatically create a snap pool for the volume. The created volume is now a master volume. 9. I am not able to map to the secondary volume. Answer: Secondary volumes cannot be presented to any hosts. 10. I cannot remove the primary volume from a set. Answer: Only a secondary volume can be removed. If you want to remove the primary volume, first make the other volume the primary volume, and then make the original primary volume a secondary volume. You can then remove the volume. 11. I cant expand a primary and secondary volumes in the replication set. Answer: Master volumes cannot be expanded, because both the primary and the secondary volumes are master volumes; they cant be expanded even in a prepared state. In the context of the HP P2000 Array System Remote Snap Software, volume expansion also causes problems because both the primary and the secondary volumes must be identical in size. This prohibits expanding volumes which are part of the set. 12. What is the MaxRetryTime? Answer: MaxRetryTime is the maximum time in seconds to retry a single replication. If this value is zero, there will be an infinite number of retries. This is valid only when error Policy is set to RETRY. A retry for a replication occurs every five minutes if an error is encountered. That is, a five-minute delay occurs in between retry attempts. If the delta time from the current time to the initial retry time is greater than the MaxRetryTime, the replication is suspended. While the MaxRetryTime field does not have granularity in terms of what can be set in the field, the behavior of the retry will have a five-minute granularity.

SummaryThe HP P2000 Array System Remote Snap Software provides array-based, remote replication with a flexible architecture and simple management, and supports both Ethernet and FC technology. The software protects against detrimental impacts to application performance, while the snapshot-based replication technology minimizes the amount of data transferred. The HP P2000 Array System Remote Snap Software enables the use of multiple recovery points for daily backups, access to data in remote sites, and business continuity when critical failures occur.

GlossarySecondary volumeThe replication volume residing on a remote system. This volume is also a normal master volume and appears as a secondary volume once it is part of a replication set. It cannot be mapped to any hosts. Replication-prepared volumeThe replication volume residing on a remote system that has not been initialized with the first initiate replication command. A user can create the volume using the SMU/CLI and can use it when creating a replication set. The default option after the replication setup wizard is to immediately perform the initiate replication command; its a good idea to perform this during setup, for example, in the replication of VSS-creating snapshots.

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Primary volumeA master volume becomes a primary volume when it is used in the creation of a replication set. It is the source from which replication snapshots are taken and copied. It is externally accessible to host(s) and can be mapped for the host I/O. Replication setThe association between the source volume (primary volume) and the destination volume (secondary). A replication set is a set of volumes associated with one another for the purposes of replicating data. To replicate data from one master volume to another, you must create a replication set to associate the two volumes. A replication set is a concept that spans systems. In other words, the volumes that are part of a replication set are not necessarily (and not likely) located on the same system. It is not a volume, but an association of volumes. A master volume is part of exactly one replication set. Replication snapshotReplication snapshots are a special form of the existing snapshot functionality. They are explicitly used in replication and do not require or count against a snapshot license. Replication imageThe representation of a replication snapshot at both the local and remote systems. In the SMU, clicking on the table shown in right pane displays both the local and Remote Snapshot information associated with a particular replication image. The name of the replication image is the time at which it was created. Sync pointsReplication snapshots are retained both on the primary volume and the secondary volume. When a matching pair of snapshots is retained on both the primary and secondary volumes, they are referred to as sync points. VSS HW ProviderA software driver supplied by the storage array vendor that enables the vendors storage array to interact with the Microsoft Server Virtual Snapshot Services framework (VSS). VSS RequestorA software tool or application that manages the execution of user Snapshot Service commands. VSS WriterA software driver supplied by the Windows Server Application vendor that enables the application to interact with the Microsoft VSS framework.

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For more information HP P2000 G3 Modular Smart Array Systemsh10010.www1.hp.com/wwpc/us/en/sm/WF05a/12169-304616-241493-241493-241493-4118559.html bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02520779/c02520779.pdf h18000.www1.hp.com/products/quickspecs/13551_div/13551_div.pdf bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02520791/c02520791.pdf bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02520788/c02520788.pdf

HP P2000 G3 Modular Smart Array System CLI Reference Guide HP P2000 G3 FC Modular Smart Array System QuickSpecs

HP P2000 G3 Modular Smart Array System SMU User Guide

HP P2000 G3 Modular Smart Array System Event Descriptions Reference Guide

To learn more about using HP P2000 Array System Remote Snap Software, visit: http://h18006.www1.hp.com/products/storage/software/p2000rs/index.html

Copyright 20102011 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein. Microsoft and Windows are U.S. registered trademarks of Microsoft Corporation 4AA1-0977ENW, Created June 2010; Updated July 2011, Rev. 2