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Use a copy storage pool to back up one or more primary storage pools. See Table 20 and Backing Up Storage Pools for more information. When you define a copy storage pool, be prepared to provide some or all of the information in Table 19.
Table 19. Information for Defining a Copy Storage Pool
Information | Explanation |
---|---|
Device class | Specifies the name of the device class assigned for the storage pool. This is a required parameter. |
Pool type | Specifies that you want to define a copy storage pool. This is a required parameter. Updating a storage pool cannot change whether the pool is a primary or copy storage pool. |
Access mode | Defines access to volumes in the storage pool for user operations (such
as backup and restore) and system operations (such as reclamation).
Possible values are:
|
Maximum number of scratch volumes | When you specify a value greater than zero, the server 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 Adding Scratch Volumes to an Automated Library Device. |
Collocation | When collocation is enabled, 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 Copy Storage Pools. |
Reclamation threshold | Specifies when to initiate reclamation of volumes in the copy storage
pool. Reclamation is a process that moves any remaining active,
fragmented files from one volume to another volume, thus making the original
volume available for reuse. A volume is eligible for reclamation when
the percentage of unused space on the volume is greater than the reclaim
parameter value.
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. |
Reuse delay period | Specifies 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 Reclaimed Volumes. |
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.
Table 20 compares the characteristics of primary and copy storage
pools.
Table 20. Comparing Primary and Copy Storage Pools
Characteristic | Primary storage pool | Copy storage pool |
---|---|---|
Destination for backed-up or archived files (specified in backup or archive copy groups) | Yes | No |
Destination for space-managed files (specified in the management class) | Yes | No |
Offsite access mode for volumes | No | Yes, except for volumes with device type SERVER |
Destroyed access mode for volumes | Yes | No |
Random access storage volumes | Yes | No |
Sequential access storage volumes | Yes | Yes |
Contents | Client files (backup versions, archived files, space-managed files) | Copies of files that are stored in primary storage pools |
Moving data allowed | Within the same primary storage pool, or to any primary storage pool | Within the same pool only.
If volumes are offsite, data is copied from the original files in primary storage pools. |
Collocation | Yes (sequential access storage pools only) | Yes |
Reclamation | Yes (sequential access storage pools only) | Yes
Virtual volumes (volumes with device type SERVER) and offsite volumes are handled differently. For details, see Reclamation of Volumes with the Device Type of SERVER and Reclamation of Offsite Volumes. |
File deletion | Files are deleted:
| Files are deleted:
|