Use this command to define a primary storage pool or a copy storage pool. You use a primary storage pool as the destination for backup files, archive files, or files migrated from client nodes. You use a copy storage pool to store backup copies of files that are in primary storage pools.
All volumes in a storage pool belong to the same device class. Random access storage pools use the DISK device type. After you define a random access storage pool, you must define volumes for the pool to create storage space.
Sequential access storage pools use device classes that you define for tape devices, optical devices, files on disk (FILE device type), and storage on another server (SERVER device type). To create storage space in a sequential access storage pool, you must allow scratch volumes for the pool when you define or update it, or define volumes for the pool after you define the pool. You can also do both.
The DEFINE STGPOOL command takes three forms, depending on whether you are defining a primary storage pool assigned to random access devices, a primary storage pool assigned to sequential access devices, or a copy storage pool (always assigned to sequential access devices). The syntax and parameters for each form are defined separately.
Use this command to define a primary storage pool assigned to random access devices.
Privilege Class
To issue this command, you must have system privilege.
Syntax
.-POoltype--=--PRimary--. >>-DEFine STGpool--pool_name--DISK----+-----------------------+-> '-POoltype--=--PRimary--' >-----+------------------------------+--------------------------> '-DESCription--=--description--' .-ACCess--=--READWrite-------. >-----+----------------------------+----------------------------> '-ACCess--=--+-READWrite---+-' +-READOnly----+ '-UNAVailable-' .-MAXSIze--=--NOLimit------------. >-----+--------------------------------+------------------------> '-MAXSIze--=--maximum_file_size--' .-HIghmig--=--90-------. >-----+----------------------------+---+----------------------+-> '-NEXTstgpool--=--pool_name--' '-HIghmig--=--percent--' .-LOwmig--=--70-------. .-CAChe--=--No------. >-----+---------------------+---+-------------------+-----------> '-LOwmig--=--percent--' '-CAChe--=--+-No--+-' '-Yes-' .-MIGPRocess--=--1-------. .-MIGDelay--=--0-----. >-----+------------------------+---+--------------------+-------> '-MIGPRocess--=--number--' '-MIGDelay--=--days--' .-MIGContinue--=--Yes-----. >-----+-------------------------+------------------------------>< '-MIGContinue--=--+-No--+-' '-Yes-'
Parameters
Server processes can move files within the volumes in the storage pool. However, no new writes are permitted to volumes in the storage pool from volumes outside the storage pool.
If this storage pool has been specified as a subordinate storage pool (with the NEXTSTGPOOL parameter) and is defined as readonly, the storage pool is skipped when server processes attempt to write files to the storage pool.
Server processes can move files within the volumes in the storage pool and can also move or copy files from this storage pool to another storage pool. However, no new writes are permitted to volumes in the storage pool from volumes outside the storage pool.
If this storage pool has been specified as a subordinate storage pool (with the NEXTSTGPOOL parameter) and is defined as unavailable, the storage pool is skipped when server processes attempt to write files to the storage pool.
Scale factor | Meaning |
K | kilobyte |
M | megabyte |
G | gigabyte |
T | terabyte |
If a file exceeds the maximum size and no pool is specified as the next storage pool in the hierarchy, the server does not store the file. If a file exceeds the maximum size and a pool is specified as the next storage pool, the server stores the file in the next storage pool that can accept the file size. If you specify the next storage pool parameter, at least one storage pool in your hierarchy should have no limit on the maximum size of a file. By having no limit on the size for at least one pool, you ensure that no matter what its size, the server can store the file.
For logical files that are part of an aggregate, the server considers the size of the aggregate to be the file size. Therefore, the server does not store logical files that are smaller than the maximum size limit if the files are part of an aggregate that is larger than the maximum size limit.
If you do not specify a next storage pool, the server cannot migrate files from this storage pool and cannot store in another storage pool files that exceed the maximum size for this storage pool.
You cannot create a chain of storage pools that leads to an endless loop through the NEXTSTGPOOL parameter. At least one storage pool in the hierarchy must have no value specified for NEXTSTGPOOL.
When the storage pool exceeds the high migration threshold, the server can start migration of files by node, to the next storage pool, as defined with the NEXTSTGPOOL parameter. You can specify HIGHMIG=100 to prevent migration for this storage pool.
When the storage pool reaches the low migration threshold, the server does not start migration of another node's files. Because all file spaces that belong to a node are migrated together, the occupancy of the storage pool can fall below the value you specified for this parameter. You can set LOWMIG=0 to permit migration to empty the storage pool.
Using cache may improve the retrievability of files, but may affect the performance of other processes. See Administrator's Guide for details.
During migration, the server runs this number of processes in parallel to provide the potential for improved migration rates.
If you want the server to count the number of days based only on when a file was stored and not when it was retrieved, use the NORETRIEVEDATE server option.
Because you can require that files remain in the storage pool for a minimum number of days, the server may migrate all eligible files to the next storage pool yet not meet the low migration threshold. This parameter allows you to specify whether the server is allowed to continue the migration process by migrating files that do not satisfy the migration delay time.
If you allow more than one migration process for the storage pool, some files that do not satisfy the migration delay time may be migrated unnecessarily. As one process migrates files that satisfy the migration delay time, a second process could begin migrating files that do not satisfy the migration delay time to meet the low migration threshold. The first process that is still migrating files that satisfy the migration delay time might have, by itself, caused the low migration threshold to be met.
Examples
Task
Define a primary storage pool, POOL1, to use the DISK device class, with caching enabled. Limit the maximum file size to 5MB. Store any files larger than 5MB in subordinate storage pools beginning with the PROG2 storage pool. Set the high migration threshold to 70 percent, and the low migration threshold to 30 percent.
Use this command to define a primary storage pool assigned to sequential access devices.
Privilege Class
To issue this command, you must have system privilege.
Syntax
>>-DEFine STGpool--pool_name--device_class_name-----------------> .-POoltype--=--PRimary--. >-----+-----------------------+---------------------------------> '-POoltype--=--PRimary--' >-----+------------------------------+--------------------------> '-DESCription--=--description--' .-ACCess--=--READWrite-------. >-----+----------------------------+----------------------------> '-ACCess--=--+-READWrite---+-' +-READOnly----+ '-UNAVailable-' .-MAXSIze--=--NOLimit------------. >-----+--------------------------------+------------------------> '-MAXSIze--=--maximum_file_size--' .-HIghmig--=--90-------. >-----+----------------------------+---+----------------------+-> '-NEXTstgpool--=--pool_name--' '-HIghmig--=--percent--' .-LOwmig--=--70-------. .-REClaim--=--60-------. >-----+---------------------+---+----------------------+--------> '-LOwmig--=--percent--' '-REClaim--=--percent--' >-----+-------------------------------+-------------------------> '-RECLAIMSTGpool--=--pool_name--' .-COLlocate--=--No------------. >-----+-----------------------------+---MAXSCRatch--=--number---> '-COLlocate--=--+-No--------+-' +-Yes-------+ '-FILespace-' .-REUsedelay--=--0-----. >-----+----------------------+---+---------------------------+--> '-REUsedelay--=--days--' '-OVFLOcation--=--location--' .-MIGDelay--=--0-----. .-MIGContinue--=--Yes-----. >-----+--------------------+---+-------------------------+----->< '-MIGDelay--=--days--' '-MIGContinue--=--+-No--+-' '-Yes-'
Parameters
Server processes can move files within the volumes in the storage pool. However, no new writes are permitted to volumes in the storage pool from volumes outside the storage pool.
If this storage pool has been specified as a subordinate storage pool (with the NEXTSTGPOOL parameter) and is defined as readonly, the storage pool is skipped when server processes attempt to write files to the storage pool.
Server processes can move files within the volumes in the storage pool and can also move or copy files from this storage pool to another storage pool. However, no new writes are permitted to volumes in the storage pool from volumes outside the storage pool.
If this storage pool has been specified as a subordinate storage pool (with the NEXTSTGPOOL parameter) and is defined as unavailable, the storage pool is skipped when server processes attempt to write files to the storage pool.
Scale factor | Meaning |
K | kilobyte |
M | megabyte |
G | gigabyte |
T | terabyte |
If a file exceeds the maximum size and no pool is specified as the next storage pool in the hierarchy, the server does not store the file. If a file exceeds the maximum size and a pool is specified as the next storage pool, the server stores the file in the next storage pool that can accept the file size. If you specify the next storage pool parameter, at least one storage pool in your hierarchy should have no limit on the maximum size of a file. By having no limit on the size for at least one pool, you ensure that no matter what its size, the server can store the file.
For logical files that are part of an aggregate, the server considers the size of the aggregate to be the file size. Therefore, the server does not store logical files that are smaller than the maximum size limit if the files are part of an aggregate that is larger than the maximum size limit.
Note: | This size limit applies only when the server is storing files during a session with a client. The limit does not apply when you move data from one pool to another, either manually or automatically through storage pool migration. |
If you do not specify a next storage pool, the server cannot migrate files from this storage pool and cannot store in another storage pool files that exceed the maximum size for this storage pool.
You cannot create a chain of storage pools that leads to an endless loop through the NEXTSTGPOOL parameter. At least one storage pool in the hierarchy must have no value specified for NEXTSTGPOOL.
When the storage pool exceeds the high migration threshold, the server can start migration of files by volume to the next storage pool defined for the pool. You can set the high migration threshold to 100 to prevent migration for the storage pool.
When the storage pool reaches the low migration threshold, the server does not start migration of files from another volume. You can set the low migration threshold to 0 to permit migration to empty the storage pool.
For storage pools that use WORM devices, the default value is 100 to prevent reclamation from occurring. This is the default because a WORM volume is not reusable. If necessary, you can lower the value to allow the server to consolidate data onto fewer volumes. Volumes emptied by reclamation can be checked out of the library, freeing slots for new volumes.
Specify a value of 50 percent or greater for this parameter so that files stored on two volumes can be combined onto a single output volume.
A reclaim storage pool is most useful for a storage pool that has only one drive in its library. When you specify this parameter, the server moves all data from reclaimed volumes to the reclaim storage pool regardless of the number of drives in the library.
To move data from the reclaim storage pool back to the original storage pool, use the storage pool hierarchy. Specify the original storage pool as the next storage pool for the reclaim storage 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 needed to collocate files for storing and the number of volumes required. For details, see Administrator's Guide.
The value specified for this parameter is used to estimate the total number of volumes available in the storage pool and the corresponding estimated capacity for the storage pool.
Scratch volumes are automatically deleted from the storage pool when they become empty. When scratch volumes with the device type of FILE are deleted, the space that the volumes occupied is freed by the server and returned to the file system.
Important: | Use this parameter to help ensure that when you restore the database to an earlier level, database references to files in the storage pool are still valid. You must set this parameter to a value greater than the number of days you plan to retain the oldest database backup. The number of days specified for this parameter should be the same as the number specified for the SET DRMDBBACKUPEXPIREDAYS command. For more information, see Administrator's Guide. |
Because you can require that files remain in the storage pool for a minimum number of days, the server may migrate all eligible files to the next storage pool yet not meet the low migration threshold. This parameter allows you to specify whether the server is allowed to continue migration by migrating files that do not satisfy the migration delay time.
Examples
Task
Define a primary storage pool named 8MMPOOL to the 8MMTAPE device class (with a device type of 8MM) with a maximum file size of 5MB. Store any files larger than 5MB in subordinate pools, beginning with POOL1. Enable collocation of files for client nodes. Allow as many as 5 scratch volumes for this storage pool.
Use this command to define a copy storage pool assigned to sequential access devices.
Privilege Class
To issue this command, you must have system privilege.
Syntax
>>-DEFine STGpool--pool_name--device_class_name-----------------> >----POoltype--=--COpy----+------------------------------+------> '-DESCription--=--description--' .-ACCess--=--READWrite-------. >-----+----------------------------+----------------------------> '-ACCess--=--+-READWrite---+-' +-READOnly----+ '-UNAVailable-' .-COLlocate--=--No------------. >-----+-----------------------------+---------------------------> '-COLlocate--=--+-No--------+-' +-Yes-------+ '-FILespace-' .-REClaim--=--100------. >-----+----------------------+--MAXSCRatch--=--number-----------> '-REClaim--=--percent--' .-REUsedelay--=--0-----. >-----+----------------------+---+---------------------------+->< '-REUsedelay--=--days--' '-OVFLOcation--=--location--'
Parameters
Server processes can move files within the volumes in the storage pool. The server can use files in the copy storage pool to restore files to primary storage pools. However, no new writes are permitted to volumes in the copy storage pool from volumes outside the storage pool. A storage pool cannot be backed up to the copy storage pool.
Server processes can move files within the volumes in the storage pool. The server can use files in the copy storage pool to restore files to primary storage pools. However, no new writes are permitted to volumes in the copy storage pool from volumes outside the storage pool. A storage pool cannot be backed up to the copy storage 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 needed to collocate files for storing and the number of volumes required. For details, see Administrator's Guide.
Possible values are:
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 a copy 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 copy storage pool that is onsite. The process then writes these files to an available volume in the original copy storage pool. Effectively, these files are moved back to the onsite location. However, the files could 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 copy storage pools.
The value specified for this parameter is used to estimate the total number of volumes available in the copy storage pool and the corresponding estimated capacity for the copy storage 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 copy storage 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.
Important: | Use this parameter to help ensure that when you restore the database to an earlier level, database references to files in the copy storage pool are still valid. You must set this parameter to a value greater than the number of days you plan to retain the oldest database backup. The number of days specified for this parameter should be the same as the number specified for the SET DRMDBBACKUPEXPIREDAYS command. For more information, see Administrator's Guide. |
Examples
Task
Define a copy storage pool, TAPEPOOL2, to the DC480 device class. Allow up to 50 scratch volumes for this pool. Delay the reuse of volumes for 45 days.
Table 77. Commands Related to DEFINE STGPOOL
Command | Description |
---|---|
BACKUP DB | Backs up the TSM database to sequential access volumes. |
BACKUP STGPOOL | Backs up a primary storage pool to a copy storage pool. |
DEFINE DEVCLASS | Defines a device class. |
DEFINE VOLUME | Assigns a volume to be used for storage within a specified storage pool. |
DELETE STGPOOL | Deletes a storage pool from server storage. |
MOVE MEDIA | Moves storage pool volumes that are managed by an automated library. |
QUERY DEVCLASS | Displays information about device classes. |
QUERY STGPOOL | Displays information about storage pools. |
RESTORE STGPOOL | Restores files to a primary storage pool from copy storage pools. |
RESTORE VOLUME | Restores files stored on specified volumes in a primary storage pool from copy storage pools. |
SET DRMPRIMSTGPOOL | Specifies that primary storage pools are managed by DRM. |
UPDATE STGPOOL | Changes the attributes of a storage pool. |