Pillar Axiom 600 Storage System
 
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In this Document

Goal

Fix

Applies to:

Goal

Guidelines for Lun Migration

Fix

In order to do LUN Quality of Service migrations, please adhere to the following:
1) Do not attempt more than ONE migration at a time as this will reduce performance during the migration process.
2) Once the migration is done (the task MonitorBackgroundLUNMigrationTask is complete and the Axiom logged the following event "Modify LUN by administrator succeeded", check the UnpreparedSystemCapacity to make sure it is "ZERO" before starting the next migration. You can run the following pdscli command to check for the UnpreparedSystemCapacity in the SataHardDiskDrives storage class as indicated by the arrow outlined in the below example:

pdscli sub -u administrator -p pillar -H axiom_ip_or_dns_name GetStorageConfig
Header
ProtocolVersion: 0.1
SessionKey: c9c0faac1ec302173c211b29767ed609
Time: 2012-01-31T09:58:23-08:00
ClientData: pdscli
RequestStatus: Succeeded
Error List
GetStorageConfigResponse
TotalSystemCapacity: 17390
UsedSystemCapacity: 5177
FreeSystemCapacity: 12213
UnpreparedSystemCapacity: 0
CommittedSystemCapacity: 5177
StorageClassUsage[1]
StorageClass: MultiLevelCellSolidStateDrives
TotalSystemCapacity: 0
UsedSystemCapacity: 0
FreeSystemCapacity: 0
UnpreparedSystemCapacity: 0
PotentialUsageList
PotentialUsage[1]
Redundancy: Standard
LargestVolumeCapacity: 0
PotentialUsage[2]
Redundancy: Double
LargestVolumeCapacity: 0
StorageClassUsage[2]
StorageClass: SataHardDiskDrives
TotalSystemCapacity: 14455
UsedSystemCapacity: 5177
FreeSystemCapacity: 9278
UnpreparedSystemCapacity: 0 <- this is the one we want, the unprepared capacity for the SATA class.
PotentialUsageList
PotentialUsage[1]
Redundancy: Standard
LargestVolumeCapacity: 7731
PotentialUsage[2]
Redundancy: Double
LargestVolumeCapacity: 3864
StorageClassUsage[3]
StorageClass: FibreChannelHardDiskDrives
TotalSystemCapacity: 2935
UsedSystemCapacity: 0
FreeSystemCapacity: 2935
UnpreparedSystemCapacity: 0
PotentialUsageList
PotentialUsage[1]
Redundancy: Standard
LargestVolumeCapacity: 2667
PotentialUsage[2]
Redundancy: Double
LargestVolumeCapacity: 1333
StorageClassUsage[4]
StorageClass: SingleLevelCellSolid StateDrives
TotalSystemCapacity: 0
UsedSystemCapacity: 0
FreeSystemCapacity: 0
UnpreparedSystemCapacity: 0
PotentialUsageList
PotentialUsage[1]
Redundancy: Standard
LargestVolumeCapacity: 0
PotentialUsage[2]
Redundancy: Double
LargestVolumeCapacit y: 0
StorageClassUsage[2] is for SATA, [3] for FC, [1] for multi-cell SSD, [4] for single-cell SSD.

3) Run command storage_allocation to see the new LUN distribution across the bricks.
You can use the axiomcli script to view what Bricks each LUN is allocated on. If you log into the Axiom GUI as administrator and click "Support" tab -> under "Utilities Download" click "Command Line Interface" select "Download CLI for <host> ".

You can use the storage_allocation command, below is an example from a windows host:
C:\pdscli> .\axiomcli.exe
Pillar Data Systems AxiomONE CLI (040000-000500)
Copyright (C) 2003, 2010 Pillar Data Systems, Inc
All rights reserved
Axiom nohost> axiom_login
Axiomhost: krusty.cs.ca
Username: administrator
Password: ******
Login Succeeded

*****************************************************
** **
** This is a company computer system with access **
** restricted to those with proper authorization. **
** Authorized parties are restricted to those **
** functions which have been assigned to perform **
** work related duties. Any unauthorized access **
** will be investigated and prosecuted to the **
** full extent of the law. If you are not an **
** authorized user, disconnect now. **
** **
*****************************************************

Axiom krusty.cs.ca> storage_allocation -list -details -extents
OR, you can output to a file
Axiom krusty.cs.ca> storage_allocation -list -details -extents -csv extents.csv

Both commands will list all the LUNs and which Bricks they are allocated on. The extents will be listed as they are laid out on the bricks.

Action Plan:
-------------
1) Identify the LUN(s) that you want to migrate.
2) Once identified, open the LUN properties and click the Quality of Service tab to view the current settings.
3) Change Priority vs. other Volumes of the LUN from its current setting to the desired band. (For example, changing from 'archive' to 'medium')
NOTE: Prior to selecting OK to execute this task, ensure that the 'Temporary' box is NOT checked followed by OK to execute the migration process. 
4) The LUN status will change to 'Configuring' for about 30 seconds and then a MonitorBackgroundLUN MigrationTask will appear in the background. This is the period of time in which performance will be affected.
5) Once the first migration is complete, run the scripts GetStorageConfig and Storage_allocation (step2 and step3). Ensure the output of UnpreparedSystemCapacity is zero and make sure that the LUN is in the new band and on different bricks.
6) Once you confirmed that the LUN is in the right band, you change the QoS back to the LUN's original setting. If you wish to keep the LUN in a different band, make the appropriate modifications. If not, make sure the 'Temporary' box is not checked and Click OK.
7) Wait until the migration back to the original setting is complete, ensure the output of UnpreparedSystemCapacity is zero and check storage_allocation for the new distribution.
8) Once complete, begin processing the next LUN and follow steps: 2-8 until all LUNs have completed migration.

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