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DEFINE STGPOOL (Define a container-copy storage pool)

Use this command to define a container-copy storage pool to hold a copy of data from a directory-container storage pool.

Privilege class

To issue this command, you must have system privilege.

Syntax

Read syntax diagramSkip visual syntax diagram
>>-DEFine STGpool--pool_name--device_class_name----------------->

>--POoltype--=--COPYCONtainer--MAXSCRatch--=--number------------>

   .-STGType--=--Devclass-.                                    
>--+----------------------+--+-----------------------------+---->
   '-STGType--=--Devclass-'  '-DESCription--=--description-'   

   .-ACCess--=--READWrite-------.   
>--+----------------------------+------------------------------->
   '-ACCess--=--+-READWrite---+-'   
                +-READOnly----+     
                '-UNAVailable-'     

   .-PROTECTPRocess--=--2------.  .-REClaim--=--100-----.   
>--+---------------------------+--+---------------------+------->
   '-PROTECTPRocess--=--number-'  '-REClaim--=--percent-'   

   .-REUsedelay--=--0----.   
>--+---------------------+-------------------------------------><
   '-REUsedelay--=--days-'   

Parameters

pool_name (Required)
Specifies the name of the container-copy storage pool. The name must be unique, and the maximum length is 30 characters.
device_class_name (Required)
Specifies the name of the sequential access device class to which this storage pool is assigned.
Restriction: You cannot specify the following device class types:
  • DISK
  • FILE
  • CENTERA
  • NAS
  • REMOVABLEFILE
  • SERVER
Restriction: Virtual tape libraries are not supported, regardless of which library type is defined. Only physical tape is supported.
POoltype=COPYCONtainer (Required)
Specifies that you want to define a container-copy storage pool. A container-copy storage pool is used only to store a copy of data from a directory-container storage pool.
MAXSCRatch (Required)
Specifies the maximum number of scratch volumes that the server can request for this storage pool. You can specify an integer in the range 0 - 100000000. If the server can request scratch volumes as needed, you do not have to define each volume to be used.

The value of this parameter is used to estimate the total number of volumes that are 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. However, if the access mode for a scratch volume is OFFSITE, the volume is not deleted from the storage pool until the access mode is changed. An administrator can then query the server for empty, offsite scratch volumes and return them to the onsite location.

STGType=Devclass
Specifies the type of storage that you want to define for a storage pool. This parameter is optional.
DESCription
Specifies a description of the storage pool. This parameter is optional. The maximum length of the description is 255 characters. Enclose the description in quotation marks if it contains any blank characters.
ACCess
Specifies how server processes such as storage-pool protection and repair can access data in the storage pool. This parameter is optional. The default value is READWRITE. You can specify one of the following values:
READWrite
Specifies that the server can read and write to volumes in the storage pool.
READOnly
Specifies that the server can only read volumes in the storage pool. The server can use data in the storage pool to restore extents to directory-container storage pools. No operations that write to the container-copy storage pool are allowed.
UNAVailable
Specifies that the server cannot access data that is stored on volumes in the storage pool.
PROTECTPRocess
Specifies the maximum number of parallel processes that are used when you issue the PROTECT STGPOOL command to copy data to this pool from a directory-container storage pool. This parameter is optional. Enter a value in the range 1 - 20. The default value is 2.

The time that is required to complete the copy operation might be decreased by using multiple, parallel processes. However, in some cases when multiple processes are running, one or more of the processes must wait to use a volume that is already in use by a different process.

When you specify this value, consider the number of logical and physical drives that can be dedicated to the copy operation. To access a tape volume, the server uses a mount point and a drive. The number of available mount points and drives depends on the mount limit of the device class for the storage pool, and on other server and system activity.

This parameter is ignored if you use the PREVIEW=YES option on the PROTECT STGPOOL command. In that case, only one process is used and no mount points or drives are needed.

REClaim
Specifies when a volume becomes eligible for reclamation and reuse. Specify eligibility as the percentage of a volume's space that is occupied by extents that are no longer stored in the associated directory-container storage pool. Reclamation moves any extents that are still stored in the associated directory-container storage pool from eligible volumes to other volumes. Reclamation occurs only when a PROTECT STGPOOL command stores data into this storage pool.

This parameter is optional. You can specify an integer in the range 1 - 100. The default value is 100, which means that volumes in this storage pool are not reclaimed.

The server determines that the volume is a candidate for reclamation if the percentage of reclaimable space on a volume is greater than the reclamation threshold of the storage pool.

By setting the reclaim value to 50 percent or greater, data that is moved from two reclaimed volumes uses no more than the equivalent of one new volume. The preferred method is to specify a reclamation value in the range 90 - 100.

REUsedelay
Specifies the number of days that must elapse after all extents are deleted from a volume before the volume can be rewritten or returned to scratch status. This parameter is optional. You can specify an integer in the range 0 - 9999. The default value is 0, which means that a volume can be rewritten or returned to scratch status as soon as all the extents are deleted from the volume.
Tip: Use this parameter to ensure that when you restore the database to an earlier level, database references to extents 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. If you use disaster recovery manager, the number of days that are specified for this parameter must be the same as the number specified for the SET DRMDBBACKUPEXPIREDAYS command.

Example: Define a container-copy storage pool with an LTO7A device class

Define a container-copy storage pool, CONTAINER1_COPY2, to the LTO7A device class. Allow up to 50 scratch volumes for this pool. Delay the reuse of volumes for 45 days.
define stgpool container1_copy2 lto7a pooltype=copycontainer
 maxscratch=50 reusedelay=45
Table 1. Commands related to DEFINE STGPOOL (Define a container-copy storage pool)
Command Description
DEFINE STGPOOL (directory-container) Define a directory-container storage pool.
PROTECT STGPOOL Protects a directory-container storage pool.
QUERY STGPOOL Displays information about storage pools.
REPAIR STGPOOL Repairs a directory-container storage pool.
UPDATE STGPOOL (container-copy) Update a container-copy storage pool that stores copies of data from a directory-container storage pool.
UPDATE STGPOOL (directory-container) Update a directory-container storage pool.