DEFINE STGPOOL (Define a primary storage pool for copying data to tape)

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Use this command to define a primary storage pool that is known as a cold-data-cache storage pool, which is used in operations to copy data from IBM Storage Protect Plus to tape storage. The data from an IBM Storage Protect Plus object client is initially written to a cold-data-cache storage pool on the IBM Storage Protect server. Then, the data is moved to a tape device or virtual tape library (VTL).

When you define a cold-data-cache storage pool, a device class is automatically created to which the storage pool is defined. Only object client data can be stored on or restored from this storage pool type.

Restrictions: The following restrictions apply to cold-data-cache storage pools:

The object client must be an IBM Storage Protect Plus server.
Replication and deduplication of cold-data-cache storage pools are not supported.
Unlike other sequential-access primary storage pools, you cannot specify the MAXSCRATCH parameter when you define cold-data-cache storage pools. The MAXSCRATCH parameter is set to 5000 by default. However, you can issue the UPDATE STGPOOL command to change this value.
You cannot select specific data to migrate. All data that is written to the cold-data-cache storage pool is subject to migration.

Privilege class

To issue this command, you must have system privilege.

Syntax

Notes:

¹ When you specify STGTYPE=COLDDATACACHE, you must specify the DIRECTORY parameter to enable the automatic creation of the device class.

Parameters

pool_name (Required)

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

POoltype=PRimary

Specifies that you want to define a primary storage pool. This parameter is optional. The default value is PRIMARY.

STGType=COLDDATACache (Required)

Specifies the type of storage. This parameter is required to define a storage pool of this type. The value must be COLDDATACACHE.

COLDDATACache: Specifies that the storage pool is used for copy operations to tape. Only data from eligible object clients can be stored in this type of storage pool.
Restriction: Cold-data-cache storage pools cannot be specified as next storage pools of any storage pool, including other storage pools of type COLDDATACACHE.

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 client nodes and server processes (such as migration and 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.

If this storage pool was specified as a subordinate storage pool (with the NEXTSTGPOOL parameter) and the storage pool has the ACCESS=READONLY parameter setting, the storage pool is skipped when server processes attempt to write files to 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.

If this storage pool was specified as a subordinate storage pool (with the NEXTSTGPOOL parameter) and the storage pool has the ACCESS=UNAVAILABLE parameter setting, the storage pool is skipped when server processes attempt to write files to the storage pool.

NEXTstgpool (Required)

Specifies a primary storage pool to which files are migrated. You cannot migrate data from a sequential-access storage pool to a random-access storage pool. This parameter is required when you define a cold-data-cache storage pool.

Restrictions: The following restrictions apply when you specify the NEXTSTGPOOL parameter for cold-data-cache storage pools:

The next storage pool must use a tape-based device class.
Data deduplication must not be enabled for the next storage pool.
The next storage pool cannot have its own next storage pool.
The next storage pool must have the MAXSIZE parameter set to NOLIMIT.

If the newly-defined storage pool does not have a next storage pool, the server cannot migrate files from the new storage pool and cannot store files that exceed the maximum size for this storage pool in another storage pool.

If the next storage pool has insufficient space, has the NEXTSTPOOL parameter set, or has a limit specified on the MAXSIZE parameter, data is not migrated to that storage pool. In these cases, the server issues a message and data migration fails.

DIRectory (Required)

Specifies one or more directories that can be used for the cold-data-cache storage pool. If you specify STGTYPE=COLDDATACACHE, you must specify the DIRECTORY parameter because one or more directories are required for the automatic creation of the device class. You can update the directories used by the cold-data-cache storage pool at a later point by issuing the UPDATE DEVCLASS command.

To specify multiple directories, separate the names with commas with no intervening spaces.

MIGPRocess

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

When calculating the value for this parameter, consider the number of sequential storage pools that will be involved with the migration, and the number of logical and physical drives that can be dedicated to the operation. To access a sequential-access volume, IBM Storage Protect 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 IBM Storage Protect and system activity and on the mount limits of the device classes for the sequential-access storage pools that are involved in the migration.

For example, suppose that you want to simultaneously migrate the files from volumes in two primary sequential-access storage pools and that you want to specify three processes for each of the storage pools. The storage pools have the same device class. Assuming that the storage pool to which files are being migrated has the same device class as the storage pool from which files are being migrated, each process requires two mount points and, if the device type is not FILE, two drives. (One drive is for the input volume, and the other drive is for the output volume.) To run six migration processes simultaneously, at least 12 mount points and 12 drives are required. The device class for the storage pools must have a mount limit of at least 12.

If the number of migration processes that 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 time that is specified by the MOUNTWAIT parameter, the migration processes end. For information about specifying the MOUNTWAIT parameter, see DEFINE DEVCLASS (Define a device class).

The IBM Storage Protect server will start the specified number of migration processes regardless of the number of volumes that are eligible for migration. For example, if you specify 10 migration processes and only 6 volumes are eligible for migration, the server will start 10 processes and 4 of them will finish without processing a volume.

Tip: When you specify this parameter, consider whether the simultaneous-write function is enabled for server data migration. Each migration process requires a mount point and a drive for each copy storage pool and active-data pool that is defined to the target storage pool.

Restriction: This parameter is not available for storage pools that use the following data formats:

NETAPPDUMP
CELERRADUMP
NDMPDUMP

REMOVERESToredcopybeforelifetimeend

Specifies that data that is restored to the cold-data-cache storage pool because of a request from IBM Storage Protect Plus can be deleted before the specified expiration date for that data. This parameter is relevant if the occupancy of the cold-data-cache storage pool is nearing capacity. This parameter is optional. The default value is NO.

Data is eligible for early deletion according to a defined time threshold, specified in days, according to the following sequence:

Data that was copied to the cold-data-cache storage pool and read more than a specified number of days ago. The oldest data is deleted first.
Data that was copied to the cold-data-cache storage pool more than a specified number of days ago. The most recently copied data is deleted first.

YES: Specifies that data that is restored to the cold-data-cache storage pool because of request from the object client can be deleted from the storage pool before the specified expiration period is reached. Only data that is eligible for early deletion according to the defined thresholds and criteria is deleted.
NO: Specifies that data that is restored to the cold-data-cache storage pool because of a request from the object client is not subject to deletion when the storage-pool occupancy nears capacity.

Example: Define a primary storage pool for copying data from IBM Storage Protect Plus to tape

Define a primary storage pool that is named PLUSCOPYPOOL as a COLDDATACACHE storage type. The creation of an associated device class is enabled automatically. Define a next storage pool that is named POOL1. Enable collocation of files for client nodes.

define stgpool pluscopypool stgtype=colddatacache
 nextstgpool=pool1 directory=dir_list

Related commands

Table 1. Commands related to DEFINE STGPOOL (Define a primary storage pool for copying data to tape)
Command	Description
QUERY STGPOOL	Displays information about storage pools.
UPDATE STGPOOL (cold-data-cache)	Update a cold-data-cache storage pool.