Use the DEFINE STGPOOL command to name a set of volumes as a primary storage pool or a copy storage pool. The volumes in a pool belong to the same device class. A primary storage pool is used as the destination for backup files, archive files, or files migrated from client nodes. A copy storage pool is used to store backup copies of files that are in primary storage pools.
During installation, ADSM provides three predefined random access storage pools:
Use this command to increase ADSM data storage capacity by defining additional storage pools. You can define storage pools as necessary to manage your storage.
You can restrict administrator authority, by storage pool, to control administrator access to your data storage.
If you want to migrate files from one primary storage pool to another, you must specify the NEXTSTGPOOL parameter. This parameter links primary storage pools together into a hierarchy for data storage.
To determine the name of the device class (and the corresponding device type) to which you want the storage pool assigned, use the QUERY DEVCLASS command.
After you define a storage pool, you can use the DEFINE VOLUME command to assign volumes to the storage pool.
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. The syntax and parameters for each form are defined separately.
Privilege Class
To issue this command, you must have system privilege.
Syntax for Defining Random Access Storage Pools
.-POoltype--=--PRimary---.
>>-DEFine STGpool--poolname--DISK---+------------------------+-->
'-POoltype--=--PRimary---'
>----+------------------------------+--------------------------->
'-DESCription--=--description--'
.-ACCess--=--READWrite--------.
>---+-----------------------------+----------------------------->
'-ACCess--=--+-READWrite---+--'
+-READOnly----+
'-UNAVailable-'
.-MAXSIze--=--NOLimit-------.
>----+---------------------------+------------------------------>
'-MAXSIze--=--maxfilesize---'
>----+---------------------------+------------------------------>
'-NEXTstgpool--=--poolname--'
.-HIghmig--=--90-------------. .-LOwmig--=--70------------.
>---+----------------------------+--+--------------------------+>
'-HIghmig--=--highmigvalue---' '-LOwmig--=--lowmigvalue---'
.-CAChe--=--No-------. .-MIGPRocess--=--1--------------.
>----+--------------------+--+-------------------------------+-><
'-CAChe--=--+-No--+--' '-MIGPRocess--=--numprocesses---'
'-Yes-'
Parameters for Defining a Random Access Storage Pool
No new writes are permitted to the volumes in the storage pool from other volumes outside the storage pool. However, system processes (like reclamation) are permitted to move files within the volumes in 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 system processes (like migration) attempt to write files to the storage pool.
No new writes are permitted to volumes in the storage pool from other volumes outside the storage pool. However, system processes (like reclamation) are permitted to move files within the volumes in the storage pool. Files can also be moved or copied from this storage pool to another 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 system processes (like migration) attempt to write files to the storage pool.
To limit the maximum physical file size, specify an integer (1 to 999999) followed by a scale factor. Scale factors and their meanings are:
For example, MAXSIZE=5G specifies that the maximum file size for this storage pool is 5 gigabytes.
If a file exceeds the maximum size and no pool is specified as the NEXTSTGPOOL, the file is not stored. If a file exceeds the maximum size and a pool is specified as the NEXTSTGPOOL, the file is stored in the next storage pool that can accept the file size. If you specify the NEXTSTGPOOL parameter, at least one storage pool in your hierarchy should have a MAXSIZE value of NOLIMIT. By setting MAXSIZE to NOLIMIT for at least one pool, you ensure that no matter what its size, a file can be stored somewhere.
A pool specified with the NEXTSTGPOOL parameter must be a primary storage pool. A copy storage pool cannot be specified.
If you do not specify a value for this parameter, migration cannot occur and files that exceed the value specified for the MAXSIZE parameter cannot be placed in another 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 occupancy exceeds the value for this parameter, ADSM can initiate migration, 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 (assuming you have defined the NEXTSTGPOOL parameter).
When the storage pool occupancy reaches the value for this parameter, ADSM will not initiate 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.
Caching improves the retrievability of files that have been migrated to sequential access storage pools by permitting cached copies of files to remain on the storage pool. The cached copies are available, if needed, or can be overwritten when necessary. The default value is NO. Possible values are:
During migration, these processes are performed in parallel to provide the potential for improved migration rates.
Syntax for Defining Primary Sequential Access Storage Pools
>>-DEFine STGpool--poolname--devclassname----------------------->
.-POoltype--=--PRimary---.
>---+------------------------+---------------------------------->
'-POoltype--=--PRimary---'
>----+------------------------------+--------------------------->
'-DESCription--=--description--'
.-ACCess--=--READWrite--------.
>---+-----------------------------+----------------------------->
'-ACCess--=--+-READWrite---+--'
+-READOnly----+
'-UNAVailable-'
.-MAXSIze--=--NOLimit-------.
>----+---------------------------+------------------------------>
'-MAXSIze--=--maxfilesize---'
>----+---------------------------+------------------------------>
'-NEXTstgpool--=--poolname--'
>---+------------------------------+---------------------------->
'-RECLAIMSTGpool--=--poolname--'
.-HIghmig--=--90-------------. .-LOwmig--=--70------------.
>---+----------------------------+--+--------------------------+>
'-HIghmig--=--highmigvalue---' '-LOwmig--=--lowmigvalue---'
.-COLlocate--=--No-------------.
>----+------------------------------+--------------------------->
'-COLlocate--=--+-No--------+--'
+-Yes-------+
'-FILespace-'
.-REClaim--=--60-------------.
>----+----------------------------+----------------------------->
'-REClaim--=--reclaimvalue---'
.-REUsedelay--=--0------.
>----MAXSCRatch--=--maxscratchvalue---+-----------------------+->
'-REUsedelay--=--days---'
>----+--------------------------------+------------------------><
'-OVFLOcation--=--locationname---'
Parameters for Defining a Primary Sequential Access Storage Pool
No new writes are permitted to the volumes in the storage pool from other volumes outside the storage pool. However, system processes (like reclamation) are permitted to move files within the volumes in 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 system processes (like migration) attempt to write files to the storage pool.
No new writes are permitted to volumes in the storage pool from other volumes outside the storage pool. However, system processes (like reclamation) are permitted to move files within the volumes in the storage pool. Files can also be moved or copied from this storage pool to another 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 system processes (like migration) attempt to write files to the storage pool.
To limit the maximum physical file size, specify an integer (1 to 999999) followed by a scale factor. Scale factors and their meanings are:
For example, MAXSIZE=5G specifies that the maximum file size for this storage pool is 5 gigabytes.
If a file exceeds the maximum size and no pool is specified as the NEXTSTGPOOL, the file is not stored. If a file exceeds the maximum size and a pool is specified as the NEXTSTGPOOL, the file is stored in the next storage pool that can accept the file size. If you specify the NEXTSTGPOOL parameter, at least one storage pool in your hierarchy should have a MAXSIZE value of NOLIMIT. By setting MAXSIZE to NOLIMIT for at least one pool, you ensure that no matter what its size, a file can be stored somewhere.
A pool specified with the NEXTSTGPOOL parameter must be a primary storage pool. A copy storage pool cannot be specified.
If you do not specify a value for this parameter, migration cannot occur from this storage pool and files that exceed the value specified for the MAXSIZE parameter cannot be placed in another 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.
Specifies another storage pool as a target for reclaimed data. This parameter is primarily for use with storage pools that have only one drive in its library. This parameter allows the volume to be reclaimed to be mounted in its library and the data is then moved to the specified reclaim storage pool.
This parameter must be an existing primary sequential storage pool. This parameter is optional, however, if this parameter is used all data will be reclaimed to that storage pool regardless of the number of drives in that library.
The reclaim storage pool itself must be defined as a primary storage pool. There are no restrictions on this storage pool's definition, but it should be defined with a NEXTSTGPOOL= value that will migrate its data back into the data storage hierarchy. Because its primary function is to collect reclaimed data, its NEXTSTGPOOL= value should be the same storage pool from which the data was reclaimed.
When the storage pool occupancy exceeds the value for this parameter, ADSM can initiate migration, by volume, to the next storage pool, as defined with the NEXTSTGPOOL parameter. You can specify HIGHMIG=100 to prevent migration for this storage pool (assuming you have defined the NEXTSTGPOOL parameter).
When the storage pool occupancy reaches the value for this parameter, ADSM will not initiate migration of files from another volume. Because all files that are on a single volume 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.
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. Collocation may not be useful on systems with only one or two sequential devices. For additional information, see ADSM Administrator's Guide.
Possible values are:
Space becomes fragmented as files on a volume are deleted because of processes such as expiration or file space deletion. The amount of space that can be reclaimed on a volume increases as files on the volume are deleted. When the percentage of space that can be reclaimed on a volume rises above the value for the RECLAIM parameter, the volume is reclaimed. Active files on the volume are rewritten to other volumes in the storage pool, making the original volume available for new files.
It is recommended that you 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.
| Note: | Once a sector of WORM optical media has been written to, it cannot be written over. This prevents WORM volumes from being reclaimed. Therefore, when storage pools are defined to a WORM device class, the default reclaim value is set to 100 to prevent reclamation from occurring. You can specify a value other than the default regardless of the device type of the device class. This allows users with storage pools assigned to device type of WORM to consolidate data onto fewer volumes, and free slots in automated libraries.To dump more than 2GB of data onto the 12 or 14-inch WORM media, ADSM with WORM support must be run on Version 4.1.4 of AIX to overcome a filesystem limitation. |
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 ADSM and returned to the file system.
By specifying this parameter, you can ensure that the database could be restored to an earlier level and database references to files in the storage pool would still be valid.
Usage Notes
The migration occupancy represented by the HIGHMIG and LOWMIG parameter is computed differently for random and sequential access storage pools:
Syntax for Defining Copy Storage Pools
>>-DEFine STGpool--poolname--devclassname--POoltype--=--COpy---->
>---+------------------------------+---------------------------->
'-DESCription--=--description--'
.-ACCess--=--READWrite--------.
>---+-----------------------------+----------------------------->
'-ACCess--=--+-READWrite---+--'
+-READOnly----+
'-UNAVailable-'
.-COLlocate--=--No-------------.
>----+------------------------------+--------------------------->
'-COLlocate--=--+-No--------+--'
+-Yes-------+
'-FILespace-'
.-REClaim--=--100------------.
>----+----------------------------+----------------------------->
'-REClaim--=--reclaimvalue---'
.-REUsedelay--=--0------.
>---MAXSCRatch--=--maxscratchvalue---+-----------------------+-->
'-REUsedelay--=--days---'
>----+--------------------------------+------------------------><
'-OVFLOcation--=--locationname---'
Parameters for Defining a Copy Storage Pool
No new writes are permitted to the volumes in the copy storage pool from other volumes outside the storage pool. Files cannot be backed up to the copy storage pool, but existing backup copies can be restored. System processes (like reclamation) are permitted to move files within the volumes in the copy storage pool.
No new writes are permitted to volumes in the copy storage pool from other volumes outside the storage pool. Files cannot be backed up to the copy storage pool, but existing backup copies can be restored. System processes (like reclamation) are permitted to move files within the volumes in 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. Collocation may not be useful on systems with only one or two sequential devices. For additional information, see ADSM Administrator's Guide.
Possible values are:
The amount of space that can be reclaimed on a volume increases as files on the volume are deleted because of processes such as expiration or file space deletion. It is recommended that you 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.
For offsite storage pool volumes, when a copy 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 that is onsite, and then write these files to an available volume in the original copy storage pool. Effectively, these files are moved back to the onsite location, although they 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.
| Note: | Once a sector of WORM optical media has been written to, it cannot be written over. This prevents WORM volumes from being reclaimed. Therefore, when storage pools are defined to a WORM device class, the default reclaim value is set to 100 to prevent reclamation from occurring. You can specify a value other than the default regardless of the device type of the device class. This allows users with storage pools assigned to device type of WORM to consolidate data onto fewer volumes, and free slots in automated libraries.To dump more than 2GB of data onto the 12 or 14-inch WORM media, ADSM with WORM support must be run on Version 4.1.4 of AIX to overcome a filesystem limitation. |
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 will not be deleted from the copy storage pool until the access mode is changed; this allows an administrator to query ADSM 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 ADSM and returned to the file system.
| Important: | Specifying this parameter, you can ensure that the database can be restored
to an earlier level and database references to files in the copy storage pool
are still valid. For this to happen, you must set this parameter to a
value greater than the number of days you plan on retaining 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 additional information, refer to ADSM Administrator's Guide. |
Examples
Task 1
Define a primary storage pool, POOL1, to the DISK device class, with caching enabled. The maximum file size is limited to 5MB, with a high migration threshold of 70 percent, and a low migration threshold of 30 percent. Any files larger than 5MB are stored in subordinate storage pools beginning with the PROG2 storage pool.
Task 2
Define a primary storage pool named POOLA to the ENDOBYTE device class (with a device type of 8MM)with a maximum file size of 5MB. Any files larger than 5MB are stored in subordinate pools, beginning with POOL1. Collocation is enabled for the storage pool. As many as 5 scratch volumes can be requested for this storage pool.
Task 3
Define a copy storage pool, COPYSTG, to the DC480 device class. Include "Copy Storage Pool" as part of the description for this pool.
Related Commands
Table 63. Commands Related to DEFINE STGPOOL
| Command | Description |
|---|---|
| BACKUP DB | Backs up the ADSM database to sequential access volumes. |
| BACKUP STGPOOL | Backs up a primary storage pool to a copy storage pool. |
| DEFINE DEVCLASS | Defines a device class that can be used for storage pools, importing, or exporting. |
| DEFINE VOLUME | Assigns a volume to be used for storage within a specified storage pool. |
| DELETE STGPOOL | Deletes a storage pool from server storage. |
| QUERY DEVCLASS | Displays information about one or more device classes. |
| QUERY STGPOOL | Displays information about one or more 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. |