This section provides examples of how you can set up a
storage pool hierarchy for an organization in your installation.
| Task | Required Privilege Class |
|---|---|
| Define storage pools | System |
| Update storage pool information | System or unrestricted storage |
When you define a primary storage pool, be prepared to
provide some or all of the information shown in Table 18. Some information applies only to random access storage pools or only
to sequential access storage pools.
Table 18. Information for Defining a Storage Pool
| Information | Explanation | Applies to Random Access | Applies to Sequential Access |
|---|---|---|---|
| Device class | Specifies the name of the device class assigned for the storage pool. This is a required parameter. | Yes | Yes |
| Pool type | Specifies that you want to define a primary storage pool (the default). Once you define a storage pool, you cannot change whether it is a primary or a copy storage pool. | Yes | Yes |
| Access mode | Defines access to volumes in the storage pool for user operations (such
as back up and restore) and system operations (such as reclamation and server
migration). Possible values are:
| Yes | Yes |
| Maximum file size | To exclude large files from a storage pool, set a maximum file
size. The maximum file size applies to the size of a physical file (a
single client file or an aggregate of client files).
Do not set a maximum file size for the last storage pool in the hierarchy unless you want to exclude very large files from being stored in server storage. | Yes | Yes |
| Name of the next storage pool | Specifies the name of the next storage pool in the storage pool hierarchy, where files can be migrated or stored. See "The Storage Pool Hierarchy". | Yes | Yes |
| Migration thresholds | Specifies a percentage of storage pool occupancy at which ADSM begins migrating files to the next storage pool (high threshold) and the percentage when migration stops (low threshold). See "Migration of Files in a Storage Pool Hierarchy". | Yes | Yes |
| Migration process | Specifies the number of processes that are used for migrating files from this storage pool. | Yes | -- |
| Cache | Enables or disables cache. When cache is enabled, copies of files migrated by the server to the next storage pool are left on disk after the migration. In this way, a retrieval request can be satisfied quickly. See "The Use of Cache on Disk Storage Pools". | Yes | -- |
| Maximum number of scratch volumes | When you specify a value greater than zero, ADSM dynamically acquires
scratch volumes when needed, up to this maximum number. This is a
required parameter.
For automated libraries, set this value equal to the physical capacity of the library. See "Maintaining a Supply of Scratch Volumes in an Automated Library". | -- | Yes |
| Collocation | Collocation is a process in which the server attempts to keep all files belonging to a client node or a client file space on a minimal number of sequential access storage volumes. See "Collocation on Sequential Access Storage Pools". | -- | Yes |
| Reclamation threshold | Specifies what percentage of reclaimable space can accumulate on a volume before the server initiates a space reclamation process for the volume. See "Choosing a Reclamation Threshold". | -- | Yes |
| Reclamation storage pool | Specifies the name of the storage pool to be used for storing data from volumes being reclaimed in this storage pool. Use for storage pools whose device class only has one drive or mount point. See "Reclaiming Volumes in a Storage Pool with One Drive". | -- | Yes |
| Reuse delay period | Specifies an integer that defines the number of days that must elapse after all of the files have been deleted from a volume, before the volume can be rewritten or returned to the scratch pool. See "Delaying Reuse of Sequential Access Volumes". | -- | Yes |
| Overflow location | Specifies the name of a location where volumes are stored when they are ejected from an automated library by the MOVE MEDIA command. Use for a storage pool that is associated with an automated library or an external library. See "Managing a Full Library". | -- | Yes |
For this example, suppose you have determined that an engineering department requires a separate storage hierarchy. You want the department's backed up files to go to a disk storage pool. When that pool fills, you want the files to migrate to a tape storage pool. You want the pools to have the following characteristics:
You can define the storage pools in a storage pool hierarchy from the top down or from the bottom up. Defining the hierarchy from the bottom up requires fewer steps. To define the hierarchy from the bottom up, perform the following steps:
define stgpool backtape tape description='tape storage pool for engineering backups' maxsize=nolimit collocate=yes maxscratch=100
define stgpool engback1 disk description='disk storage pool for engineering backups' maxsize=5M nextstgpool=backtape highmig=85 lowmig=40
If you have already defined the storage pool at the top of the hierarchy, you can update the storage hierarchy to include a new storage pool.
For example, suppose you had already defined the ENGBACK1 disk storage pool. Now you have decided to set up a tape storage pool to which files from ENGBACK1 can migrate. Perform the following steps to define the new tape storage pool and update the hierarchy:
define stgpool backtape tape description='tape storage pool for engineering backups' maxsize=nolimit collocate=yes maxscratch=100
update stgpool engback1 nextstgpool=backtape
When you define a copy storage pool, be prepared to provide some or all of the following information:
For automated libraries, set this value equal to the physical capacity of the library. See "Maintaining a Supply of Scratch Volumes in an Automated Library".
Reclamation processing works differently for offsite storage pool volumes and virtual volumes. When a copy storage pool volume that is offsite becomes eligible for reclamation, the reclamation process attempts to retrieve the active files on the reclaimable volume from a primary or copy storage pool volume that is onsite. The process then writes these files to an available volume in the original copy storage pool. See "Reclamation for Copy Storage Pools" and "Reclamation of Volumes with the Device Type of SERVER" for more details.
Assume you need to maintain copies of the files stored in BACKUPPOOL, ARCHIVEPOOL, and SPACEMGPOOL (default disk storage pools) for disaster recovery purposes. You want to create a copy storage pool named DISASTER-RECOVERY. You decide to use only scratch tapes in the new pool, setting the maximum number of scratch volumes to an appropriate value. You enter the following command:
define stgpool disaster-recovery tapeclass pooltype=copy maxscratch=100
To store data in the new storage pool, you must back up the primary storage pools (BACKUPPOOL, ARCHIVEPOOL, and SPACEMGPOOL) to the DISASTER-RECOVERY pool. See "Backing Up Storage Pools".