4.1 IBM TSM V7 Storage Pools Overview and Introduction


A storage pool is a named set of volumes that belongs to the same device class, which is the destination of backed up or archived data. A device class is a grouping of like devices, such as disk or tape. The purpose of storage pools is matching user requirements for data with the physical characteristics of storage devices. For example, if you need immediate access to certain data, you can define a storage pool that consists of storage volumes on high-performance disks. You can associate this storage pool as a destination for files by binding the appropriate management class.

Tivoli Storage Manager Storage Pools Functions

Files can be placed initially on different storage pools according to the stated storage management policy. Files are then moved automatically to other devices to adhere to free space, space utilization, performance, and recovery requirements.

A storage destination identifies the storage pool where client data goes when it is backed up, archived, or migrated. The management class, which is a part of policy management, includes the backup and archive copy group definitions. These definitions specify the storage destination. 

Also Read: TSM Storage Pool Concepts (V7 Revised)

An administrator with system, storage, or operator privilege can manage data storage, including the planning, preparing, monitoring, and deleting of storage volumes and storage pools. The tasks depend on the level of the privilege class.


TSM Storage pools
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TSM Storage Pools Features
  • They are a collection of like media, same device class.
  • Provide storage for backed up, archived, or migrated files.
  • Support a variety of devices.
  • Stores data in defined storage pool volumes.
  • First, client sends data to server
  • Server writes data to disk pool
  • Moves data from disk pool to the next defined storage pool
  • Server records data storage information in Tivoli Storage Manager database

 Types of Storage Pools

There 3 types of storage pools in Tivoli Storage Manager

Primary Storage Pool: It is the first destination of client backups. It can either Disk, Tape or FILE device class.

Copy storage pool: Backup copies of active and inactive data from primary storage pools for off-site storage. Copy storage pools contain backups of the primary storage pools. You can backup storage pool data to disk, which uses a file device class, or removable media, such as tape.

Active-data pools: Backup copies only of active data for fast restoration of client data. Active-data pools only contain the latest, or active version of data. Use them in the following situations
  • With sequential-access disk (FILE)
  • With sequential-access tape or optical
  • To collocate active versions of backup data
  • For backup data only, not for archive or HSM data
  • With the disaster recovery manager
Defining storage pools
During TSM Server installation, Tivoli Storage Manager provides the following predefined random access storage pools
  • BACKUPPOOL: A storage destination for user files that are backed up to the server
  • ARCHIVEPOOL: A storage destination for user files that are archived to the server
  • SPACEMGPOOL: A storage destination for files that are migrated from user nodes.
Example:
define stgpool testpool disk description="test storage pool" maxsize=5m highmig=70 lowmig=30 cache=yes nextstgpool=destpool

Defining a primary & copy storage pool:

Use the following command to define a primary storage pool
DEFine STGpool poolname devclass 

For example: DEFine STGpool tapepool devclass=tape

For a copy storage pool, you need to specify the pool type. Use the following command to define a copy storage pool
  DEFine STGpool poolname devclass pooltype=copy

For example: DEFine STGpool copy1 devclass=tape pooltype=copy

Updating and querying storage pools

Use the update stgpool command to change any parameter in an existing primary, copy, or active-data storage pool. If you do not explicitly update a parameter, it remains unchanged. The parameters to update are the same as the parameters that are defined for a storage pool. 
UPDate STGpool poolname

Use the query stgpool command to show information about one or more storage pools.
Query STGpool poolname

The query occupancy command shows the following information
  • Node name
  • Type, backup, archive, or space managed
  • File space name and number
  • Storage pool names
  • Number of files
  • Physical and logical space occupied
Query OCCupancy nodename

Overflow location for the storage pool media

Use database tracking to change the location of a volume to a specified overflow location. The Tivoli Storage Manager administrator uses overflow storage pools to better manage storage pools that grow beyond the capacity of the library. Database tracking is used primarily for long-term archive storage pools where the data is maintained on-site but is rarely retrieved for Tivoli Storage Manager processing.

Also Read: What is Cloud Container Storagepool ?

The first stage in implementing an overflow storage pool is defining the location of the volumes when they overflow from the library. You can define the location by using either the define stgpool or update stgpool command and the OVFLOCATION parameter. This parameter is a text description of where the volumes are found. 
UPDate STGpool tapepoolpool ovflocation=locker100

The second step is moving the media to the overflow location. Issue the move media command, which moves media from the library to the overflow location. For example, to move all full volumes in the specified storage pool out of the library, use the following command
move media * stgpool=tapepool

You can show the overflow location for a storage pool by using the query stgpool f=d (format=detail) command. This command produces output that shows the storage pool name, type, associated device class, estimated capacity, and the overflow location. The overflow location has the following attributes
  • A physical location, defined with the MOVE MEDIA command
  • Used when library becomes full
  • Applicable to primary or copypool volumes
  • Associates the location of volumes outside of the library
  • You must move volumes to the overflow location manually   

Backing up primary storage pools

We use copy storage pools for taking backup of primary storage pools. Copy storage pool media are send to offsite for Disaster recovery purposes. To backup a primary storage pool to a copy pool, use the following command
BAckup STGpool primary_pool_name copy_pool_name

If a file already exists in the copy storage pool, the file is not backed up unless the copy of the file in the copy storage pool is marked as damaged. However, a new copy is not created if the file in the primary storage pool is also marked as damaged. In a random-access storage pool, neither cached copies of migrated files nor damaged primary files are backed up. 

Deleting storage pools and volumes

You can delete the storagepools at anytime if you no longer need them. You first have to delete all the volumes assigned to that storagepool before deleting any storagepool.
delete stgpool tapepool






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