Use this command to define an active-data pool assigned to sequential-access devices.
To issue this command, you must have system privilege.
>>-DEFine STGpool--pool_name--device_class_name-----------------> >--POoltype--=--ACTIVEdata--+-----------------------------+-----> '-DESCription--=--description-' .-ACCess--=--READWrite-------. >--+----------------------------+-------------------------------> '-ACCess--=--+-READWrite---+-' +-READOnly----+ '-UNAVailable-' .-COLlocate--=--No------------. .-REClaim--=--60------. >--+-----------------------------+--+---------------------+-----> '-COLlocate--=--+-No--------+-' '-REClaim--=--percent-' +-GRoup-----+ +-NODe------+ '-FIlespace-' .-RECLAIMPRocess--=--1------. >--+---------------------------+--------------------------------> '-RECLAIMPRocess--=--number-' .-RECLAMATIONType--=--THRESHold---------. >--+---------------------------------------+--------------------> | (1) | '-RECLAMATIONType--=--+-THRESHold-+-----' '-SNAPlock--' .-OFFSITERECLAIMLimit--=--NOLimit-. >--+---------------------------------+--MAXSCRatch--=--number---> '-OFFSITERECLAIMLimit--=--number--' .-REUsedelay--=--0----. >--+---------------------+--+--------------------------+--------> '-REUsedelay--=--days-' '-OVFLOcation--=--location-' .-DATAFormat--=--NATive-------. .-CRCData--=--No------. >--+-----------------------------+--+---------------------+-----> '-DATAFormat--=--+-NATive---+-' '-CRCData--=--+-Yes-+-' '-NONblock-' '-No--' .-DEDUPlicate--=--No----------. >--+-----------------------------+------------------------------> '-DEDUPlicate--=--+-No------+-' | (2) | '-Yes-----' .-IDENTIFYPRocess--=--0----------. >--+--------------------------------+-------------------------->< | (3) | '-IDENTIFYPRocess--=--number-----'
Server processes can move files within the volumes in the storage pool. The server can use files in the active-data pool to restore files to primary storage pools. However, no new writes are permitted to volumes in the active-data pool from volumes outside the storage pool. A storage pool cannot be copied to the active-data pool.
Server processes can move files within the volumes in the storage pool. The server can use files in the active-data pool to restore files to primary storage pools. However, no new writes are permitted to volumes in the active-data pool from volumes outside the storage pool. A storage pool cannot be copied to the active-data pool.
Collocation reduces the number of sequential access media mounts for restore, retrieve, and recall operations. However, collocation increases both the amount of server time that is needed to collocate files for storing and the number of volumes required. Collocation can also impact the number of processes migrating disks to sequential pool.
If you specify COLLOCATE=GROUP but do not define any collocation groups, or if you do not add nodes or file spaces to a collocation group, data is collocated by node. Consider tape usage when you organize client nodes or file spaces into collocation groups.
Data is collocated on the least amount of sequential access volumes.
If a storage pool contains data for a node that is a member of a collocation group and you specify COLLOCATE=NODE, the data is collocated by node.
For COLLOCATE=NODE, the server creates processes at the node level when you migrate data from disk.
For COLLOCATE=FILESPACE, the server creates processes at the file space level when you migrate data from disk.
Reclamation makes the fragmented space and space occupied by inactive backup files on volumes usable again by moving any remaining unexpired files and active backup files from one volume to another volume. This makes the original volume available for reuse. This parameter is optional. You can specify an integer from 1 to 100. The default value is 60.
When determining which volumes in a storage pool to reclaim, the Tivoli Storage Manager server first determines the reclamation threshold indicated by the RECLAIM. The server then examines the percentage of reclaimable space for each volume in the storage pool. If the percentage of reclaimable space on a volume is greater that the reclamation threshold of the storage pool, the volume is a candidate for reclamation.
When reclamation begins, the server compares the percent of reclaimable space for each volume with the reclamation threshold of 70 percent. In this example, FILEVOL2 and FILEVOL3 are candidates for reclamation because their percentages of reclaimable space are greater than 70. To determine the percentage of reclaimable space for a volume, issue the QUERY VOLUME command and specify FORMAT=DETAILED. The value in the field Pct. Reclaimable Space is the percentage of reclaimable space for the volume.
If you change the value from the default, specify a value of 50 percent or greater so that files stored on two volumes can be combined onto a single output volume.
When an active-data pool volume that is offsite becomes eligible for reclamation, the reclamation process attempts to obtain the unexpired files on the reclaimable volume from a primary or active-data pool that is onsite. The process then writes these files to an available volume in the original active-data pool. Effectively, these files are moved back to the onsite location. However, the files can be obtained from the offsite volume after a disaster if a database backup is used that references the files on the offsite volume. Because of the way reclamation works with offsite volumes, use it carefully with active-data pools.
When calculating the value for this parameter, consider the number of sequential storage pools that will be involved with the reclamation and the number of logical and physical drives that can be dedicated to the operation. To access a sequential access volume, IBM® Tivoli Storage Manager uses a mount point and, if the device type is not FILE, a physical drive. The number of available mount points and drives depends on other Tivoli Storage Manager and system activity and on the mount limits of the device classes for the sequential access storage pools that are involved in the reclamation.
For example, suppose that you want to reclaim the volumes from two sequential storage pools simultaneously and that you want to specify four processes for each of the storage pools. The storage pools have the same device class. Each process requires two mount points and, if the device type is not FILE, two drives. (One of the drives is for the input volume, and the other drive is for the output volume.) To run eight reclamation processes simultaneously, you need a total of at least 16 mount points and 16 drives. The device class for the storage pools must have a mount limit of at least 16.
If the number of reclamation processes you specify is more than the number of available mount points or drives, the processes that do not obtain mount points or drives will wait for mount points or drives to become available. If mount points or drives do not become available within the MOUNTWAIT time, the reclamation processes will end. For information about specifying the MOUNTWAIT time, see DEFINE DEVCLASS (Define a device class).
The Tivoli Storage Manager server will start the specified number of reclamation processes regardless of the number of volumes that are eligible for reclamation. For example, if you specify ten reclamation processes and only six volumes are eligible for reclamation, the server will start ten processes and four of them will complete without processing a volume.
All volumes in this storage pool are created as FILE volumes. A retention date, derived from the retention attributes in the archive copy group for the storage pool, is set in the metadata for the FILE volume using the SnapLock feature of the NetApp Data ONTAP operating system. Until the retention date has expired, the FILE volume and any data on it cannot be deleted from the physical SnapLock volume on which it is stored.
The RECLAMATIONTYPE parameter for all storage pools being defined must be the same when defined to the same device class name. The DEFINE command fails if the RECLAMATIONTYPE parameter specified is different from what is currently defined for storage pools that are already defined to the device class name.
select * from summary where activity='OFFSITE RECLAMATION'
The statistical information includes the following items: The order in which offsite volumes are reclaimed is based on the amount of unused space in a volume. (Unused space includes both space that has never been used on the volume and space that has become empty because of file deletion.) Volumes with the largest amount of unused space are reclaimed first.
For example, suppose an active-data pool contains three volumes: VOL1, VOL2, and VOL3. VOL1 has the largest amount of unused space, and VOL3 has the least amount of unused space. Suppose further that the percentage of unused space in each of the three volumes is greater than the value of the RECLAIM parameter. If you do not specify a value for the OFFSITERECLAIMLIMIT parameter, all three volumes are reclaimed when the reclamation runs. If you specify a value of 2, only VOL1 and VOL2 are reclaimed when the reclamation runs. If you specify a value of 1, only VOL1 is reclaimed.
The value specified for this parameter is used to estimate the total number of volumes available in the active-data pool and the corresponding estimated capacity for the active-data pool.
Scratch volumes are automatically deleted from the storage pool when they become empty. However, if the access mode for a scratch volume is OFFSITE, the volume is not deleted from the active-data pool until the access mode is changed. This allows an administrator to query the server for empty, offsite scratch volumes and return these to the onsite location.
When scratch volumes with the device type of FILE become empty and are deleted, the space that the volumes occupied is freed by the server and returned to the file system.
The default value for this parameter is 0. Duplicate-identification processes for a copy storage pool are not necessary if you specify duplicate-identification processes for the primary storage pool. When Tivoli Storage Manager analyzes a file in a storage pool, Tivoli Storage Manager also analyzes the file in all other storage pools.
When calculating the value for this parameter, consider the workload on the server and the amount of data requiring data deduplication. Server-side duplicate identification requires disk I/O and processor resources, so the more processes you allocate to data deduplication, the heavier the workload that you place on your system. In addition, consider the number of volumes that require processing. Server-side duplicate-identification processes work on volumes containing data that requires deduplication. If you update a storage pool, specifying that the data in the storage pool is to be deduplicated, all the volumes in the pool require processing. For this reason, you might have to define a high number of duplicate-identification processes initially. Over time, however, as existing volumes are processed, only the volumes containing new data have to be processed. When that happens, you can reduce the number of duplicate-identification processes.
define stgpool tapepool3 dc500 pooltype=activedata
maxscratch=50 reusedelay=45