Disk Admin

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Disk Administration

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Objectives

When you have completed this module you will be able to do the following:

• Describe RAID support on NetCache• Describe disk numbering conventions• Describe disk and shelf configurations

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RAID 4 Support• One Parity Disk and one or more data disks• Data striped across disks• Hot spare disk - not part of RAID array and

does not contain cached objects• Hot swapping - external disks only• RAID 0 (striping) for C1200

.

RAID support on the NetCache Appliance

The NetCache Appliance uses RAID Level 4 to ensure data integrity, even when one of the disks fails. The file system design, with the support for RAID, optimizes NetCache Appliance performance and allows you to expand the NetCache Appliance's disk storage capacity one disk at a time (except for the C720s and C110X series).

In the RAID file system, different disks play different roles. Most of the disks are data disks, and one disk in the array is the parity disk. The parity disk must be the same size as or larger than the largest data disk. After a data disk failure, the NetCache Appliance uses the parity disk in conjunction with the remaining data disks to reconstruct data previously located on the failed disk. Although the NetCache Appliance can continue to function, it automatically shuts down after 24 hours to encourage you to replace the failed disk.

In addition to data and parity disks, you can install one or more hot spare disks in the NetCache Appliance (except for the C720s and C110X). A hot-spare disk is not part of the RAID disk array and does not contain cached objects. After a disk failure, the NetCache Appliance automatically rebuilds data on the hot spare and adds the hot spare to the RAID array, thus avoiding a system shutdown.

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Fibre Channel Shelves

Loopid 0

Loopid 1

Loopid 2

Loopid 3

Loopid 4

Loopid 5

Loopid 6

Loopid 8

Loopid 9

Loopid 10

Loopid 11

Loopid 12

Loopid 13

Loopid 14

PowerSupply

PowerSupply

PowerSupply

PowerSupply

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Disk NumberingView and manage disks in NetCache Manager

and on the CLI• Disks listed by shelf and bay number or by

HA.ID• NetCache Manager lists by Shelf and Bay

number • Sysconfig –r lists disks by HA.ID• Vol status –r lists disks by HA.ID

Disk addresses You identify a disk by its address, which is listed in the HA.Disk_ID column of the output of the sysconfig -r command. In this output listing, HA refers to the host adapter and Disk_ID refers to the disk identification number. Use the disk address to do the following:

• Interpret screen messages • Identify a disk addresses.

Fibre channel disk addresses With fibre channel disks, the disk address is a combination of the disk's adapter number, port numbers, and the disk's fibre channel loop ID. To create the fibre channel loop ID, multiply the shelf ID switch value by eight, and add it to the bay number. For example, ha 8, shelf 1, disk 2 has disk ID 8.10.

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Maintenance > Disk > Management

Disk - Management

The options on the Maintenance > Disk > Management page enable you to perform the following tasks on this NetCache Appliance:

• View the type, size, and status of disks installed

• Perform disk management tasks, such as adding, removing, and replacing disks

Refer to Online Help for specific configuration information.

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Viewing Disks on CLInetcache> sysconfig -rVolume vol0 (online, normal, unmirrored) (zoned checksums)

Plex /vol0/plex0 (online, normal, active)RAID group /vol0/plex0/rg0

RAID Disk Device HA SHELF BAY CHAN Used (MB/blks) Phys (MB/blks)--------- --------- --------------- ---- -------------- -------------

-parity 6.10 6 1 2 FC:A 16979/34774016 17560/35964296 data 6.11 6 1 3 FC:A 16979/34774016 17560/35964296

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How to Formulate HA.IDHA.ID is composed of:

– Slot number of the adapter card– Shelf ID– Bay Number in the shelf– The formula for FC7, 8, 9 7 disk shelves:

adapter slot number 8 x shelf id + bay number

– The formula for DS14 disk shelves:adapter slot number 16 x shelf id + bay number

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Other sysconfig –r Output• Zone refers to disks format

– 512 BPS format – Block format, 520 BPS, not supported– Checksums written to disk every 63 strip

• Chan refers to Channel A or B– NetCache uses Chan A only– Channel B exists on Netapp filers in cluster

or multipath IO

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Other sysconfig –r output

• Unmirrored volume– State of vol0 is Unmirrored– Not sync or snap mirrored

• Plex 0 refers to sync mirroring– Volume is synchronously written twice– Supported on Netapp filers only– Sync mirroring not supported on

NetCache

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C2100

• 2 to 7 SCSI Drives• 36GB or 72GB • Hot swappable

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C1200

• 1 to 3 SCSI Drives• 36GB or 72GB • Warm swappable

.

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Disk Commands

The disk scrub command checks for media errors such as bad blocks. NetApp recommends that customers run this command onec a month to avoid a double disk failure.

Use the disk fail 4.1 command to manually fail a disk when the disk scrub command finds errors.

The disk swap and disk unswap command pertain to SCSI disks and it has no effect on FC-AL disks.

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C1200

• 1 to 3 SCSI Drives• 36GB or 72GB • Warm swappable

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High Availability via RAID Palliation

for C1200 Appliance(HARP)

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Why HARP? • Improve the exposure of the C1200 platform to disk

unreliability by enabling RAID-4

• While RAID-0 was a necessity on one disk systems, it introduced reliability concerns. On a RAID-0 volume, any hard or soft (unrecoverable media errors) disk failures resulted in: – System crash – Loss of filesytem and cache contents – Field replacement of system

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What HARP will do • Enabling RAID-4 in NetCache appliance

without NVRAM:– System memory is used in place of NVRAM– Power failures will result in a panic and the RAM

information is lost– Disk failures cause the NetCache to run in

degraded mode for five days

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User Interfaces for Disk Firmware and qual_devices

files

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Maintenance Disk Firmware

• List of firmware files present. Name is Important

• Can delete the file selected using this page• Firmware files can be uploaded either from

local machine or from ftp/http server• Commit Firmware button will apply any new

firmware for the drives present in the cache

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Maint > Disk > Firmware

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CLI Interface• disk_fw:

usage:disk_fw –c Commit new firmwaresdisk_fw -dl <url of the firmware file> Download firmwaredisk_fw -dc <url of the firmware file> Download and commit

firmwaredisk_fw -d <firmware file> Delete firmware filesdisk_fw –l List downloaded firmwaredisk_fw –x Cancel firmware download in progress

• New Firmware can be downloaded fromhttp://now.netapp.com/NOW/download/tools/diskfw/

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qual_devices File Upload• NetCache allows customers to 'add' disk support for

new disks by updating the /etc/qual_devices • Maintenance > Disk > Qual Devices

– View– Copy– Upload from local machine or ftp/http server

• http://now.netapp.com/NOW/download/tools/diskqual/

Information is filer specific but applicable to NetCache as well. Only difference is the way files are updated in Filer and NetCache

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Maintenance > Disk > Qual Devices

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http://now.netapp.com/NOW/download/tools/diskqual/

D NETAPP NTAP2770 064cD SEAGATE ST12400N 9072 512D SEAGATE ST12550N 0013 512D SEAGATE ST32430N 0000 512D SEAGATE ST43400N 0000 512D SEAGATE ST43400ND 0000 512D SEAGATE ST43401N 0000 512D SEAGATE ST43401ND 0000 512D SEAGATE ST43402ND 0111 512D SEAGATE ST15150N 0023 512D SEAGATE ST15150W 0023 512D SEAGATE ST15230N 0000 512D SEAGATE ST34572WC 0784 512D SEAGATE ST19171W 0024 512D SEAGATE ST19171FC FB59 512D SEAGATE ST39102FC NA27 512

Sample

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