-
Executive summary
...............................................................................................................................
2 What is a Virtual Tape Library?
.............................................................................................................
2 Comparing the VTL and a standard tape library
......................................................................................
3 Will different virtual and physical drive types cause problems or
affect performance? .................................. 3 Advanced
Backup to Disk technology using a Data Protector File Library
.................................................... 4
OverviewAdvanced Backup to Disk
....................................................................................................
4
Backup to disk-based devicesbenefits
..............................................................................................
5 HP Data Protector Software offers three different device types
...................................................................
6
What is a file library?
.......................................................................................................................
6 Distributed file media format (DFMF) file library
...................................................................................
8 Enhanced incremental backup (Incremental forever)
.............................................................................
9
How does enhanced incremental work in Data Protector?
............................................................... 10
Incremental forever paradigm
......................................................................................................
10
Object consolidation
......................................................................................................................
11 Space-efficient synthetic full backup (virtual full)
.................................................................................
12
VLS Automigration option
...................................................................................................................
13 VLS Automigration data copy methods
.............................................................................................
13 How to integrate and configure Automigration in Data Protector
.......................................................... 13 How
is the Automigration initiated by Data Protector
..........................................................................
16 VLS Automigration advantages
........................................................................................................
17 Limitations
.....................................................................................................................................
17
VLS versus Data Protector file libraries
..................................................................................................
18 Data Protector GUI wizard
..............................................................................................................
19 Automatic and intelligent space management
....................................................................................
19 Improved disk full handling
.............................................................................................................
19
Use caseDisk staging
......................................................................................................................
20 New file library license: B7038**
...................................................................................................
21
Advanced Backup to Disk Licensing (B7038AA/BA/CA)
................................................................ 21
HP Data Protector Software licensing using a VTL library
....................................................................
21
Summary and conclusions
...................................................................................................................
22 For more information
..........................................................................................................................
23
HP Data Protector Software Advanced Backup to Disk Integration
with Virtual Tape Libraries White paper
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2
Executive summary This white paper provides a better
understanding of the integration of HP Data Protector Software with
Virtual Tape Libraries by utilizing the Advanced Backup to Disk
functionality available with the HP Data Protector Software. After
reading this paper, you should be able to determine the difference
between a Data Protector file library device and a Virtual Library.
You should also be able to determine how to employ the licensing
structure of HP Data Protector Software to best suit your customers
needs.
What is a Virtual Tape Library? A Virtual Tape Library (VTL) is
a dedicated computing appliance that emulates the drives of a
physical tape library and stores backup images to disk. Backup
applications, like HP Data Protector Software, use the VTL emulated
tape and library devices for backups when in fact it is an
array-based appliance.
Figure 1. HP StorageWorks 6000 Virtual Library System
(VLS6000)
The VTL consists of three components: computer hardware,
application software, and a RAID-based array of disk drives. The
application software emulates a tape library and tape drives and
the RAID-based array of drives ensures no backup data is lost if a
hard drive fails. These components are frequently bundled by a
single vendor into an appliance.
The VTL allows a customer to configure virtual tape drives and
virtual tape cartridges, and to specify cartridge capacity. The
maximum number of supported virtual tape drives varies by vendor,
ranging from single digits to an unlimited number of drives. And,
unlike physical tape libraries, which require that additional tape
drives be purchased and installed, virtual tape drives can be added
to the VTL by changing the software configuration, with no
additional hardware costs.
Because the VTL emulates a tape library and its drives, it does
not require a change to the backup paradigm. When using Data
Protector Software, you would configure the device just as you
would configure any other direct/LAN/SANattached tape library and
drive.
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3
Comparing the VTL and a standard tape library Problems with
physical tape drives, robotic failures, and media lead to the
failure of several backup jobs. These problems can be difficult to
diagnose. Write errors, reported by an operating system, do not
indicate whether the media or drive is at fault. The administrator
must then spend time determining whether the media or drive caused
the problem. In addition, restoring from physical tape can involve
multiple tape cartridges. If one of these cartridges fails, the
restore most likely will be incomplete or fail altogether.
Because all VTLs use RAID storage, read and write failures are
extremely unlikely, so the VTL effectively eliminates drive and
media issues from the backup and recovery process.
Base VTL throughput can also be improved by adding more capacity
(disk drives), controllers, and Fibre Channel (FC) ports. However,
with newer tape drives capable of backing up data, with
compression, at greater than 50 MB/s, backing up large amounts of
multi-streamed data to physical tape may still be faster than the
VTL.
Performing restores from the VTL can also be faster than using
physical tape. This is likely to be the case when recovering
specific files, due to the random access of disk as compared to the
sequential access of tape. However, if huge amounts of data are
being restored, and multiple tape drives are reading data in
parallel, physical tape may be faster than the VTL.
Multiplexing or interleaving of client backup jobs to a single
tape drive is often used to keep a tape drive streaming. But, if
the tape drive cannot continue streaming, it either has to stop,
reposition the tape, and start writing againwhich has a huge impact
on performance and reliabilityor the drive has to slow down and
write data at reduced speed. Either way, backup performance is
compromised. Multiplexing also impacts restore performance.
Restoring data from a multiplexed backup takes longer because one
clients data is interleaved with many others and spread over a
larger area on the tape cartridge. A VTL uses disk and provides
random access to data. Rather than multiplex backups, each client
can be allocated a separate virtual drive. If the disk backup is
then copied to physical tape, it will not be multiplexed. Restoring
from this tape will be faster than restoring from a multiplexed
backup.
With no penalty imposed when configuring additional VTL drives
by using Data Protectors capacity-based licensing modelassuming the
maximum allowable number of drives has not been reachedvirtual
drives can be allocated specifically for restore operations. This
ensures that restores will be initiated quickly. Overall speed of
the restore operation will still depend on available bandwidth and
the size of the restore.
In most instances the VTL will be deployed as a front-end to a
traditional physical tape library. Backup data can be object copied
from the VTL to physical tape using the copy functions of Data
Protector or using the new VLS Automigration Integration.
Will different virtual and physical drive types cause problems
or affect performance? In the world of physical tape, drive types
are chosen based on a combination of performance, media capacity,
and reliability, and each has a bearing on price. These
characteristics do not translate to the VTL.
There are three factors to physical tape drive performance:
mount time, load time, and tape streaming speed. From the
perspective of data throughput, the VTL does not simulate the
performance of the physical tape drive typethat is DLT, SDLT, or
LTOselected for emulation. Read and write operations from and to
the VTL take place as fast as the disk array can process,
regardless of the chosen drive type.
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With regard to capacity, the virtual cartridges in the VTL can
be configured to whatever size is desired. Although a physical
DLT7000 drive uses a cartridge holding 35 GB of uncompressed data,
a virtual DLT7000 cartridge can be configured to store 300 GB, 1
TB, or whatever capacity is appropriate to the application. Virtual
cartridges should not be configured so large that they limit the
number of concurrently running backup jobsa VTL with 20 TB of
storage can only support 20 concurrently running backup jobs if
virtual cartridges are sized at 1 TB. If backup jobs are being
multiplexed, very large virtual cartridges can be configured.
However, the ability to avoid multiplexing is considered by many to
be a significant benefit of using a VTL.
Advanced Backup to Disk technology using a Data Protector File
Library Advanced Backup to Disk is a new functionality option for
customers running HP Data Protector Software Version 5.5 and
higher. Advanced Backup to Disk functionality in Data Protector
improves the backup process with continuous backup of transaction
log files, backup of slow clients without multiplexing, easy
resource access and sharing, plus backup in tapeless branch
offices, while offering fast and easy configuration and licensing.
Furthermore, it allows tape virtualization with easy backup
resource sharing. This new feature complements the Data Protector
backup to disk technologies of Zero Downtime Backup (ZDB), Instant
Recovery (IR), and the VTL. Advanced Backup to Disk allows your
customer to meet the demand for fast and direct restore from disk
with transparent access to data migrated to tape. This offers the
ideal solution for customers who want to stage the backup on fast
central disk space before moving it to tape.
Advanced Backup to Disk is enabled through the introduction of a
new device type called a File Library. This feature allows the HP
Data Protector Software customer to create a Data Protector file
library device as a backup and recovery point.
The file library device controls the space management of the
library automatically. It can be configured to automatically create
or extend space on your disk device to accommodate your backup. It
uses automatic retention management to allow for automatic space
re-use within your file library. The file library can restore and
back up in parallel and the technology is disk array independent so
you can deploy it with a multitude of different storage devices
from a single disk, low-cost JBOD, to the higher end storage
arrays.
The file library device is configured and used through the Data
Protector GUI. The device is conceptually similar to a tape stack
in that it consists of one or more files in container directories,
which are the equivalent of slots in a tape stack where data is
stored. In the case of the file library device, the data is stored
in a series of files called file depots, which are created each
time a backup to the device is made.
The file library device is supported on HP-UX, Microsoft
Windows, Solaris, Linux, AIX, Netware, Tru64, and OpenVMS
systems.
OverviewAdvanced Backup to Disk Customers have requirements for
increasingly larger, faster methods of backing up and restoring
data. In addition, it has become more important that the time
required for data backup and restore should be reduced to a minimum
so as not to impact/interrupt the day-to-day running of company
applications.
This may be achieved using split mirror/snapshot technologies in
ZDB configurations to create a replica of the data or through usage
of disk-based devices, which write backup data into files residing
on the disks. The ZDB concepts are not topics of this white paper;
instead the concepts of backup to disk-based devices will be
discussed in more detail.
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5
Many applications and databases frequently make small changes to
existing files or produce many new files containing
business-critical data throughout the working day. These files must
be backed up immediately to guarantee their data will not be lost.
This requirement means that a fast medium capable of storing large
amounts of data without interruption is necessary for storing
data.
Disk-based storage media has become increasingly cheaper in
recent years. At the same time, the storage capacity of disks has
risen. This has led to the availability of low-cost,
high-performance single disks and disk arrays for storing data.
Disk backup (also known as disk-to-disk backup) is becoming ever
more important. In the past, tape storage was the favored medium
for backup and restore because of its price and effectiveness in
meeting disaster recovery requirements. Today, more businesses are
augmenting their tape storage backup solutions with faster
disk-based backup solutions. This ensures faster data backup and
recovery.
Backup to disk-based devicesbenefits There are many situations
in which it is advantageous to use disk-based devices when
performing backups. Disk-based devices are, in fact, specific files
in specified directories, to which you can back up data instead of
(or in addition to) backing it up to tape. The following list
indicates some situations in which disk-based devices are
particularly useful:
Many applications and databases continuously generate a high
number of files or changed files, containing business-critical
data. Under these circumstances, it is necessary to continuously
back up the concerned files to guarantee the capability of
restoring them without data loss.
In these environments, tape devices typically have to operate in
stop/start mode because they do not receive a constant data stream.
This may result in the tape device limiting access to the concerned
files. In addition, the lifetime of the backup device may be
greatly reduced. In this case, a backup can alternatively be
performed to any disk-based device, overcoming the limitations
described. As a short-term backup solution, this is adequate in
itself. If a longer term backup solution is required, the data in
the disk-based devices can be moved periodically to tape to free up
the disk space. This process is known as disk staging.
In environments that have fast, high-capacity disk drives and
slow tape drives, you can shrink the backup window by performing
backup to disk-based devices first and moving the data to tape
later.
Disk-based devices are useful for providing fast restore
capability for recently backed up data. For example, backup data
could be kept in file devices for 24 hours to enable fast,
convenient restore without the need to stream data from tape
first.
Mechanically, a disk-based device is quicker to use than a tape.
When using a file device, there is no need to mount and unmount a
tape. When backing up or restoring a small amount of data, a
disk-based device is quicker because it does not need the
initialization time that a tape drive requires. With a file device,
there is no need to move a robotic to load or unload media, which
consumes more time in a small backup or restore. This is especially
true when restoring from an incremental backup.
The risk of media problems such as faulty tapes and tape
mounting failures are reduced to a minimum. The availability of
RAID disk configurations provides protection of data in cases where
a disk fails.
Overhead costs are reduced because there is no need for tape
handling, for example, during the performance of incremental
backups to disk.
Overall, disk-based storage space is becoming increasingly
cheaper than tape-based storage.
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6
HP Data Protector Software offers three different device types
HP Data Protector Software has a selection of devices that are
designed to do backup and restore to and from disks. These devices
are referred to as disk-based devices because they are designed to
back up data to disk as opposed to tape. The devices vary in their
functional sophistication and expected uses, and include:
File device (standalone) The file device is the simplest
disk-based device. It is a standalone device and it has to be
configured manually. It consists of a single slot to which data can
be backed up. It is not possible to change the properties of the
device after it has been created. The recommended maximum capacity
of data that can be backed up with the standalone file device is up
to 2 TB, if this file size is supported by the operating system on
which the device is running.
Jukebox The jukebox device is a logical equivalent of a tape
stacker. It contains slots whose size is defined by the user during
initial device configuration. This device is configured manually.
The jukebox properties can be altered while it is being used. Each
slot in the file jukebox device has a maximum capacity of 2 TB. The
devices maximum capacity is equal to: number of slots x 2 TB
File library device The file library device is the most
sophisticated disk-based device. It consists of multiple slots to
which you can back up data. It is designed to execute unattended
backup and restore of large amounts of data. It can be
automatically configured using a wizard in the Data Protector GUI.
As with the Jukebox, the recommended maximum storage capacity of
this device is limited only by the amount of data that can be
stored or saved in a file system by the operating system on which
the file library device is running.
Out of the three disk-based devices, the file library device is
recommended for use as an unattended backup device.
What is a file library? The file library is a new device type
introduced with HP Data Protector Software Version 5.5. It is a
group of files in one or more configured directories to which you
back up data instead of writing to a tape. The files contained in
the file library are called file depot. There is no maximum
capacity for the file library device that is set by Data Protector.
The only limit on the size of the device is determined by the
maximum size of a file, which can be saved in a file system on the
operating system on which the device is being run. For example, the
maximum size of the file library device running on Linux would be
the maximum size of a file you can save on this operating
system.
You specify the capacity of a file device when you first
configure the medium. It is possible to re-set the sizing
properties of the file library at any time during use of the device
in the Data Protector GUI.
The file library device can be located on a local hard drive, or
even on a network share, as long as Data Protector knows its path.
The directory path is defined at configuration of the file library
device. However, it is recommended to use a local disk or a disk in
SAN. Disks connected by way of NFS/CIFS links provide only a slow
connection and are sometimes unreliable.
A file library consists of configured directories that include
files where the data is stored. The directories are configured at
the initial configuration of the file library device. The files
inside are called file depot and they are created each time a
backup or copy session is made to the file library. If the amount
of data being backed up is larger than the maximum file depot size,
Data
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7
Protector creates more than a single file depot for a backup
session. The backed up object will span over two file depots. A
file depot is equivalent to a tape media in a slot, whereas the
directories represent the repository (slots) part of a library. As
a consequence, many of the known media operations can be applied,
for example, scan, format, recycle, export (non DFMF library), and
so on. However, some operations are not available, for example,
eject.
The name of each file depot is a unique identifier that is
automatically generated by Data Protector. It looks similar to the
Data Protector media ID, but actually it is not a media ID, instead
just a unique file name. For example, (including path 80 character
filename limitation):
C:\back\0100007f54106d9295058c50008.fd
Since each file depot contains backed up or copied data, a
corresponding DCBF file keeps the detail catalog information for it
in the IDB. Thus, for each file depot a corresponding DCBF file
exists, providing a logging level or catalog protection period is
specified (default).
The size of file depots is defined when you initially create the
file library device. During this process you specify all sizing
properties for the device, including the maximum size of the file
depots (see Figure 2). The sizing properties of the file depots,
although only entered once, are globally applied to each file depot
within its directory. If the size of data to be backed up within
one session is larger than the originally specified file depot
size, Data Protector automatically creates more file depots until
the allocated disk space for the file library device has been
consumed.
On Windows, the maximum recommended file depot/slot size is 5
GB, although the standalone file device has been tested on Windows
with file depots of up to 600 GB. On HP-UX, the maximum allowed
file depot size is 2 TB. However, for best performance a 5 GB depot
size is recommended.
Figure 2. Sizing properties of Data Protectors file library
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8
Analog to the file jukebox file drives can also be created;
these are called writers. The naming convention for the writers
is:
_Writer
For each newly created file library, by default there will be a
new media pool created with the naming convention _MediaPool. The
user can change this setting to any other existing mediapool of
type file.
Distributed file media format (DFMF) file library With HP Data
Protector Software Version 6.0, a new media format is
introduceddistributed file media format (DFMF). This format can
only be used with the Data Protector file library and is by default
not enabled. For enabling this DFMF format, the appropriate option
needs to be selected (see Figure 3).
Without this format Data Protector writes all data and catalog
segments into one file. This is done per session, hence each
session creates its own file. With the new media format, data
blocks are written into different files. This is done for each
file, bigger than the used block size (default 64 KB). Therefore,
for each backed up file, a dedicated file on the file library is
created, which holds the data blocks.
If a consolidation session is performed on backups that are all
located in the same file library, the data that will be
consolidated is already stored in one or more media files. The new
DFMF concept tries to reuse those files, hence instead of copying
the data blocks, they are only referred by way of pointers.
Therefore, consolidation sessions, creating virtual full, do not
copy the files hosting the data blocks. Instead, the new session
only refers to them by way of pointers. Note that only
consolidation sessions are using pointers; normal backups, both
full and incremental, are always creating new data block files.
Figure 3. Enabling distributed file media format (DFMF)
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9
Figure 4 shows conceptually the difference between the
conventional and the new DFMF format for the Data Protector 6.0
file library. Instead of putting all data blocks into one file, the
new DFMF creates several files on the file library. For each file
that is backed up, an own file is created inside the file library
to host the data blocks. The parent medium file, storing all
catalog information, is using pointers to find the data
segments.
Figure 4. Difference between conventional and new DFMF
format
Enhanced incremental backup (Incremental forever) With
conventional incremental backup, the criterion for determining
whether a file has changed since a previous backup is the files
modification time. There are cases where this criterion is not
effective. For example, if a file has been renamed, moved to a new
location, or if some of its attributes have changed, its
modification time does not change. Consequently, the file is not
backed up in an incremental backup. Such files are backed up in the
next full backup.
With enhanced incremental backup, Data Protector 6.0 introduced
its own mechanism to reliably detect whether a file has been
changed and therefore should be put into the incremental
backup.
Enhanced incremental backup reliably detects and backs up
renamed and moved files, as well as files with changes in their
attributes.
Use cases for enhanced incremental backup include:
To ensure incremental backup of files with changes in name,
location, or attributes To eliminate unnecessary full backups if
some of the selected trees change To enable subsequent object
consolidation
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10
How does enhanced incremental work in Data Protector? The first
full backup with enhanced incremental backup enabled in the file
system options of the backup specification (see Figure 5) creates
two files for each directory on each client to be backed up. Both
of these new files will contain a hash-key, one for the directory
and the other for all the files of this directory. Additionally a
timestamp is stored.
Figure 5. Enabling enhanced incremental backup
The hash-key contains the properties of the file. This
information allows Data Protector to detect nearly all changes to
the files and thus it is able to add all the modified files into an
incremental backup job. This is done by comparing the stored
hash-key with the current hash-key, generated whenever an
incremental backup is done.
Note that the hash-key does not contain the ACL information.
Therefore the enhanced incremental backup detects changes on file
permissions not by the hash-key and must still rely on OS flags,
like attribute flag on Windows.
Incremental forever paradigm The incremental forever paradigm
means that except for the first backup, where a full is performed,
only incremental backups are executed. This concept presents the
most efficient way of backing up only changed data.
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11
However, without object (backup) consolidation, the restore
process would last far too long, since nearly all backup sessions
would have to be restored as separate objects. Due to this
behavior, regular full backups are required.
Object (backup) consolidation removes this drawback. After the
first full backup, you employ Data Protectors new incremental
forever technology. To prevent the incremental forever paradigm,
Data Protector 6.0 has introduced the concept of object (backup)
consolidation into synthetic full backups or space-efficient
virtual full backups.
Object consolidation The Data Protector object consolidation
functionality enables you to merge a restore chain of a backup
object into a new, consolidated version of this object. Using this
functionality, you no longer need to run full backups. Instead, you
can run incremental backups indefinitely and consolidate the
restore chain as needed. During the object consolidation session,
Data Protector reads the backed up data from the source media,
merges the data, and writes the consolidated version to the target
media. The result of an object consolidation session is a synthetic
full backup of the specified object version.
Note: If a file was removed between two incremental backups, the
consolidated session will include the file.
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12
Synthetic backup is a backup solution that eliminates the need
to run regular full backups. Instead, incremental backups are run,
and subsequently merged with the full backup into a new, synthetic
full backup. This can be repeated indefinitely, with no need to run
a full backup again. In terms of restore speed, such a backup is
equivalent to a conventional full backup. With a synthetic backup,
all blocks (data and catalog information) are copied to a new media
(see Figure 6).
Figure 6. Object consolidation concept
Figure 6 shows how the restore chain is consolidated. The
restore chain, consisting of a full and three incremental backups,
is consolidated into a new full, named synthetic enhanced full.
After a consolidation one session with type full (synthetic,
enhanced) is listed inside the restore GUI. This session represents
the incremental backup, used for the consolidation, and the
consolidation itself.
Space-efficient synthetic full backup (virtual full) HP Data
Protector Software Version 6.0 introduced the possibility to
perform a space-efficient synthetic full, also called a virtual
full backup. By default a synthetic full copies all blocks (data
and catalog information) to a new medium. With a space-efficient
synthetic full, or virtual full, the data is not copied. Instead
pointers are used to refer to already existing data blocks. As a
result, the consolidation takes less time and avoids unnecessary
duplication of data.
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13
The following prerequisites must be fulfilled to perform a
synthetic or virtual full backup:
All the backups that will be consolidated were performed with
the enhanced incremental backup option enabled.
All incremental backups that will be consolidated reside in the
same file library. The restore chain must be complete, meaning that
all the object versions that comprise it
have the status Completed or Completed/Errors and all the media
holding these object versions are available.
The necessary backup devices are configured and the media
prepared. A Media Agent that will participate in an object
consolidation session is installed on every system. The appropriate
user rights for starting an object consolidation session (Start
backup specification)
are secured. To perform a virtual full backup, all the backups
source (full, incremental) and target (virtual full)
must reside in the same file library that uses DFMF.
VLS Automigration option Automigration is an automated copy
process without putting additional load on the SAN or the backup
application, like HP Data Protector Software. It means that that
the VLS behaves like an echo/smart copy engine that migrates the
data from the virtual cartridges on disk to a physical tape library
or another VTL which is attached to the VLS device.
VLS Automigration data copy methods The VLS Echo Copy method is
performed by the VLS without any interaction from Data Protector.
The data is asynchronously copied to the physical tape that belongs
to a dedicated physical library connected to the VLS. This copy
method creates a bit-for-bit copy which implies that Data Protector
would not be able to distinguish both media.
The other Automigration data copy method is Smart Copy. This
copy method is also performed by the VLS, but it is initiated and
controlled by Data Protector. In Data Protector terminology it is
called Media Copy. This is not a bit-by-bit copy as the tape header
of the target media is different. So, created tapes can be
distinguished and media management is enabled. Such tapes created
with Smart Copy have the Data Protector format and are readable
with every compatible tape drive that is configured in Data
Protector.
How to integrate and configure Automigration in Data Protector
HP Data Protector Software Version 6.1 enhances the existing media
copy functionality by introducing an Automigration option. This
allows the migration of backed up data from the HP StorageWorks
Virtual Library System (VLS) to a dedicated physical tape library
or another VTL that is directly connected to the VLS through Fiber
Channel. The VLS device has exclusive access and control over the
physical library.
As this physical library is not visible for Data Protector, the
VLS shows all slots of the physical tape library, which are
associated with the smart copy services, as extended functionality/
special slots (see Figure 7 for VLS Automigration dataflow and
device configuration in Data Protector).
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14
Figure 7. VLS Automigration dataflow + device configuration in
Data Protector
VLS Automigration dataflow
1.Backup from backup server or media server to VLS
2.Tape to tape copy duplicates the data from VLS directly to the
tape library
3.Tape is physically taken off site
VLS Tape library
SAN
1
2
3
Data Protector backup server
Destination library can be a VTL, too.
Smart Copy Pool for physical tape library
Imported VLS Device
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15
VLS configuration Configuration of a dedicated physical library
on the VLS (under the new Automigration tab
on the Command View VLS as can be seen in Figure 8) Smart Copy
Pool Creation for this dedicated physical tape library :
1. Click on 2. Under Destination Libraries, select Media Pools
of the of the connected physical
tape library 3. Click on 4. Fill out the required fields and
click the submit button for Smart Copy Pool Creation
For further details about Automigration configuration on VLS
side, please go to http://www.hp.com/go/VLS
Figure 8. VLS configuration
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16
Data Protector configuration Installation of the Data Protector
component VLS Automigration on the client machine. Import the VLS
as the new client type VLS device into Data Protector During import
operation, the IP address or hostname, username and password needs
to be
entered in order to gain the access to the CIMOM (Common
Interface Model Object Manager) running on a VLS device.
Enabling Automigration functionality by setting the appropriate
option Activate smart media copying by using the existing media
copy functionality
Figure 9. Data Protector configuration
Import of VLS as client type VLS device
Enabling Automigration
CIMOM configuration
How is the Automigration initiated by Data Protector With Data
Protector 6.1, the existing media copying functionality is used for
triggering the smart/media copy process as follows:
Automated smart/media copying: takes place after the completion
of a backup session (Post-backup) or at a specific time or at
regular intervals (scheduled)
Interactive smart/media copying creates a copy of a medium
containing the backed up data and can be started on demand at any
point in time
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17
VLS Automigration advantages The VLS Automigration integrated
into Data Protector brings the following benefits:
Easy management, as smart copies are managed as standard Data
Protector media copies. This means that Data Protector tracks the
status of copy operations and monitors copy sessions. The
information about the smart/media copies is stored in the IDB
Increased backup performance and significantly decreased backup
window. The fast primary backups to the VLS disk-based virtual
tapes are made with minimal impact on your environment. Smart
copying takes place as a secondary task without causing any
disruption to the application performance.
Additional protection against data loss due to the existence of
multiple copies on disk and tape.
The ability to create smart copies allows you to keep your data
available for restore or data archiving for longer periods of time
without exceeding the capacity of a virtual library.
Fast and reliable restores using the Data Protector restore
functionality.
Limitations Copies through Automigration can only be done
between slots and copy slots of the
same VTL After copy process, source and destination tape are
made non-appendable. This is the same
as for the usual media copy Media in the physical library can
only be accessed through VLS Media within the copy slots cannot be
used for other operations like backup and restore.
Further information and consideration regarding the
configuration and setup can be found in the VLS documentation and
Data Protectors manuals.
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VLS versus Data Protector file libraries The VLS should not be
confused with Data Protector file libraries. Both are disk-based
backup solutions, but the VLS is a hardware solution, and Data
Protector file libraries are a software solution. The VLS has the
following advantages over Data Protector file libraries:
VLS tape drives can be shared among multiple servers in a SAN
environment just like physical tape drives.
The VLS is optimized for sequential I/O and therefore provides
better backup performance. VLS tape drives appear as tape devices
to the server and therefore will not be included in backups
or scanned by virus scan. VLS tapes can be imported into a Data
Protector cell in the event that the cell manager is lost; file
libraries cannot.
The following comparison was taken from the VLS customer
presentation:
Choose Data Protector Advanced Backup to Disk when any of the
following are true: You want to use existing storage in your SAN or
locally attached storage. You have relatively few SAN hosts writing
to disk. Your environment is LAN only.
Choose the HP StorageWorks Virtual Library System when any of
the following are true: You have many SAN hosts writing to disk.
You want to use compression. You have high bandwidth needs for
backup.
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Data Protector GUI wizard To make the creation and configuration
of a file library as easy and user friendly as possible, a new GUI
wizard has been added, which guides the user through the few
required steps (see Figure 10).
Figure 10. Data Protector GUI
Automatic and intelligent space management An important
difference to a file jukebox is that with a newly created file
library, no slots/file depots will be created. They will
automatically be added into the file library during the usage. The
customer has only to care about the disk space needed. By default
all file depots will be non-appendable. This is very useful for the
efficient disk space management. Only one session will be stored in
one (or more) file depot. As soon the protection of the session
expires, the file depot can be re-used. In cases where the customer
has sessions with a small amount of data, backup of logical and
archive logs, the media usage policy of the media pool should be
changed to appendable.
Improved disk full handling In the past during writing data into
the file depot, there was a possibility that there was no disk
space left to complete the task. This has been solved through the
pre-allocation of that amount of disk space, which is needed to
complete the write task, in particular to complete the write of the
catalog segment.
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Use caseDisk staging The concept of disk staging is based on
backing up data in several stages to improve the performance of
backups and restores, reduce costs of storing the backed up data,
and increase the data availability and accessibility for
restore.
The backup stages consist of backing up data to media of one
type and later moving it to media of a different type. The data is
backed up to media with high performance and accessibility, but
limited capacity (for example, system disks). These backups are
usually kept accessible for restore for a period of time when a
restore is the most probable. After a certain period of time, the
data is moved to media with lower performance and accessibility,
but high capacity for storage, using the object copy
functionality.
Figure 11. Disk staging example
Some use cases where a file library as part of a disk staging
concept is very useful include:
Continuous backup of transaction log files (no overhead through
media load/unload and for tape drives there is no issue with
start/stop mode)
Backup of slow clients without multiplexing Tapeless backup of
branch offices Working similar to a virtual tape library
Restore: Fast restore from disk if data still available
there
Media Agent
NEW: direct restore from tape
Disk Agent
Disk Agent
Disk Agent
Backup
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New file library license: B7038** Advanced Backup to Disk
Licensing (B7038AA/BA/CA) Includes the license-to-use (LTU) for
1/10/100 TB of backup disk storage. Required once per terabyte (TB)
usable native capacity of backup disk storage. Usable native
capacity of a Data Protector file library is the size on disk of
all files used for the file
library, as reported by the file system. The backup disk storage
can be distributed over multiple disk arrays and systems. Does not
require any drive and library LTU. Drive and library licenses are
required for file devices,
but not for Advanced Backup to Disk. In the same way, Advanced
Backup to Disk cannot be licensed with drive and library
licenses.
It does not matter whether UNIX or Windows powers the backup
disk. The Advanced Backup to Disk license is required to back up to
a Data Protector file library or
a VTL.
HP Data Protector Software licensing using a VTL library There
are two ways to use a VTL with Data Protector. It is possible to
choose whether to use the Advanced Backup to disk or tape drive
licensing model. Within one VTL, both concepts must not been mixed.
Drive/Library extension approach
Using the traditional drive extension licensing practices, you
could license each individual virtual drive with the UX/SAN/NAS
Drive Extension (B6953AA). The Virtual Libraries that you have
created to house these drives are fully functional up to 60 slots.
If the 60-slot limit is exceeded, then library slot extensions
would be required61250 slots (B6957BA) or the unlimited slot
license (B6958BA). Using the drive extension approach can be done
but it might limit your availability to the VTL because of the lack
of licensing. This could potentially affect performance by having
too much data and not enough devices available to stream to.
Capacity-based licensing approach
Using the Advanced Backup to Disk licensing ((B7038AA/BA/CA 1TB,
10TB, 100TB), the usable native capacity of a virtual tape library
(VTL) need to be licensed. This is the size on disk of the virtual
tape library consumed by all protected Data Protector backups as
reported by the VTL. Using this licensing model, the customer can
configure as many drives and libraries as the VTL vendor allows. In
the case of the HP VLS Virtual Libraries, 64 drives in 16 libraries
can be created. This method is more favorable because you are only
limited to the capacity of the licensing you have purchased. You
can configure each device to back up a single object, allowing
high-speed sequential backup of your data. HP Data Protector
Software Advanced Backup to Disk licensing works on a per-terabyte
basis. However, due to the size on disk licensing concept,
compression rates and de-duplication rates do not need to be
considered. In case this license has been purchased before July
1st, 2008, HP is fully committed to protect investments. This means
you can choose to use this license for the VTL under the old
licensing terms: Usable native capacity of a VTL is the space
occupied by protected backups and protected backup copies and
mirrors according to the Data Protector internal database. To keep
virtual tape library licensing stress free and simple, a
compression rate of 2:1 is assumed for VTLs with no extra
charge.
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Continuing with the previous model only makes sense in case you
do not use compression or deduplication technology. Otherwise, you
get a higher value if you use previously purchased licenses under
the new licensing model. This capacity enhancement is only
available to HP Data Protector Software customers who deploy a VTL
library utilizing the Advanced Backup to Disk Licensing extension.
To utilize the capacity-based license for a VTL, select the Virtual
Tape Library option when configuring the SCSI device (see Figure
12).
Figure 12. Configuring capacity-based licensing model for a
VTL
Summary and conclusions VTLs integrate into HP Data Protector
based on the size on disk licensing concept without
considering compression rates and de-duplication rates when
capacity-based licensing is invoked. Disk staging acts as a buffer
allowing media drives to operate at maximum speeds and provide
the
option to do automatic data replication during off-peak hours.
This technique is highly recommended when backing up numerous small
files to prevent poor transfer rates to tape drive.
Single file restores are executed with an excellent performance
by disk technologies. This is very helpful for selective file
restores (particularly multiple times) where time is an important
issue. No tape must be loaded and positioned, which is a major
advantage against tape technologies.
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For more information HP Data Protector Software
http://www.hp.com/go/dataprotector
HP StorageWorks Virtual Library System (VLS)
http://www.hp.com/go/VLS
HP Performance Assessment Tools
http://www.hp.com/support/pat
Library and Tape Tools http://www.hp.com/support/tapetools
Technology for better business outcomes Copyright 2006, 2008
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.
4AA0-8760ENW Rev. 1, November 2008