DEFINE STGPOOL (Define a retention storage pool)

Privilege class

To issue this command, you must have system privilege.

Parameters

pool_name (Required)

Specifies the name of the storage pool to define. The name must be unique, and the maximum length is 30 characters.

device_class_name (Required)

Specifies the name of the device class to which this storage pool is assigned. The maximum length of the device class name is 30 characters. For retention storage pools, you can specify the following device classes only:

• 3592
• LTO
• Ecartridge

Restriction: The following device classes are not suitable for long-term data retention and are therefore not supported for retention storage pools:

• FILE
• 3590
• 4MM
• 8MM
• DLT
• Generictape

POoltype=RETention

Specifies that you want to define a retention storage pool. To define a retention storage pool, you must specify POOLTYPE=RETENTION.

DESCription

Specifies a description of the retention storage pool. This parameter is optional. The maximum length of the description is 255 characters. Enclose the description in quotation marks if it contains blank characters.

ACCess

Specifies how client nodes and server processes (such as reclamation) can access files in the storage pool. This parameter is optional. The default value is READWRITE. You can specify the following values:

READWrite

Specifies that client nodes and server processes can read and write to files stored on volumes in the storage pool.

READOnly

Specifies that client nodes can only read files from the volumes in the storage pool.

Server processes can move files within the volumes in the storage pool. However, no new write operations are permitted to volumes in the storage pool from volumes outside the storage pool.

UNAVailable

Specifies that client nodes cannot access files stored on volumes in 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 write operations are permitted to volumes in the storage pool from volumes outside the storage pool.

REClaim

Specifies when the server reclaims a volume, which is based on the percentage of reclaimable space on a volume. Reclaimable space is the amount of space that is occupied by files that are expired or deleted from the IBM Spectrum® Protect database.

Reclamation makes the fragmented space and space that is occupied by retention files on volumes usable again by moving any remaining unexpired files from one volume to another volume. This action makes the original volume available for reuse. This parameter is optional. You can specify an integer 1 - 100. The default value is 100.

Important: If you return volumes onsite to restore data, keep the default storage pool reclamation threshold value. The default value is 100. In this way, when you move retention volumes onsite by issuing the MOVE RETMEDIA command and specifying the TOSTATE=ONSITERETRIEVE parameter, storage pool reclamation processing does not interfere with the move operation.

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.

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.

Restriction: Reclamation is not possible for retention storage pool volumes that are offsite because there might not be any versions of the files available at the onsite location to use for the reclamation process.

RECLAIMPRocess

Specifies the number of parallel processes to use for reclaiming the volumes in this storage pool. This parameter is optional. Enter a value 1 - 999. The default value is 1.

When you calculate the value for this parameter, consider the following resources that are required for reclamation processing:

• The number of sequential storage pools.
• The number of logical and physical drives that can be dedicated to the operation.

To access sequential volumes, IBM Spectrum Protect uses a mount point and a physical drive.

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 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.

You can specify one or more reclamation processes for each retention storage pool. You can specify multiple concurrent reclamation processes for a single retention storage pool, which makes better use of your available tape drives. If multiple concurrent processing is not necessary, specify a value of 1 for the RECLAIMPROCESS parameter.

COLlocate

Specifies whether the server attempts to keep data, which is stored on as few volumes as possible, that belong to one of the following candidates:

• A single client node
• A group of file spaces
• A group of client nodes
• A client file space

This parameter is optional. The default value is NO.

Collocation reduces the number of sequential access media mounts for restore operations. However, collocation increases both the amount of server time that is needed to collocate files for storing and the number of volumes required.

You can specify one of the following options:

No

Specifies that collocation is disabled. The server attempts to use all available space on each volume before it selects a new volume.

GRoup

Specifies that collocation is enabled at the group level for client nodes or file spaces. For collocation groups, the server attempts to put data for nodes or file spaces that belong to the same collocation group on as few volumes as possible.

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.

For example, if a tape-based storage pool consists of data from nodes and you specify COLLOCATE=GROUP, the server completes the following actions:

• Collocates the data by group for grouped nodes. Whenever possible, the server collocates data that belongs to a group of nodes on a single tape or on as few tapes as possible. Data for a single node can also be spread across several tapes that are associated with a group.
• Collocates the data by node for ungrouped nodes. Whenever possible, the server stores the data for a single node on a single tape. All available tapes that already have data for the node are used before available space on any other tape is used.

If a tape-based storage pool consists of data from grouped file spaces and you specify COLLOCATE=GROUP, the server completes the following actions:

• Collocates by group, the data for grouped file spaces only. Whenever possible, the server collocates data that belongs to a group of file spaces on a single tape or on as few tapes as possible. Data for a single file space can also be spread across several tapes that are associated with a group.
• Collocates the data by node (for file spaces that are not explicitly defined to a file space collocation group). For example, node1 has file spaces named A, B, C, D, and E. File spaces A and B belong to a filespace collocation group but C, D, and E do not. File spaces A and B are collocated by filespace collocation group, while C, D, and E are collocated by node.

Data is collocated on the least amount of sequential access volumes.

NODe

Specifies that collocation is enabled at the client node level. For collocation groups, the server attempts to put data for one node on as few volumes as possible. If the node has multiple file spaces, the server does not try to collocate those file spaces. For compatibility with an earlier version, COLLOCATE=YES is still accepted by the server to specify collocation at the client node level.

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.

FIlespace

Specifies that collocation is enabled at the file space level for client nodes. The server attempts to place data for one node and file space on as few volumes as possible. If a node has multiple file spaces, the server attempts to place data for different file spaces on different volumes.

MAXSCRatch (Required)

Specifies the maximum number of scratch volumes that the server can request for this storage pool. You can specify an integer 0 - 100000000. By allowing the server to request scratch volumes as needed, you avoid having to define each volume to be used.

The value that is specified for this parameter is used to estimate the total number of volumes available in the retention storage pool and the corresponding estimated capacity for the retention 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 retention 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.

Tip: For server-to-server operations that use virtual volumes and that store a small amount of data, consider specifying a value for the MAXSCRATCH parameter that is higher than the value you typically specify for write operations to other types of volumes. After a write operation to a virtual volume, IBM Spectrum Protect marks the volume as FULL, even if the value of the MAXCAPACITY parameter on the device-class definition is not reached. The server does not keep virtual volumes in FILLING status and does not append to them. If the value of the MAXSCRATCH parameter is too low, server-to-server operations can fail.

REUsedelay

Specifies the number of days that must elapse after all files are deleted from a volume before the volume can be rewritten or returned to the scratch pool. This parameter is optional. You can specify an integer 0 - 9999. The default value is 0, which means that a volume can be rewritten or returned to the scratch pool as soon as all the files are deleted from the volume.

Tip: Use this parameter to ensure that when you restore the database to an earlier level, database references to files in the retention 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 that are specified for this parameter must be the same as the number specified for the SET DRMDBBACKUPEXPIREDAYS command.

OVFLOcation

Specifies the overflow location for the storage pool. The server assigns this location name to a volume that is ejected from the library by the command. This parameter is optional. The location name can be a maximum length of 255 characters. Enclose the location name in quotation marks if the location name contains any blank characters.