ARPOOL: Identifying the volumes for aggregate recovery

Explanation: ARPOOL is an optional parameter specifying a pool of volumes to be used as target volumes during an aggregate recovery.

Subparameter	Explanation
agname	ARPOOL(agname) specifies the name of the aggregate group. For agname substitute an aggregate group name that has been defined. The defined pool will be used for recovery of that aggregate group’s data sets. If no agname is specified, the command fails.
*	*ARPOOL()** specifies that the volumes are assigned to a general pool of aggregate recovery volumes. The general pool of volumes is used when recovering an aggregate group that does not have a specific ARPOOL defined.

You can use the following optional subparameters with the ARPOOL parameter.

Subparameter

Explanation

The ALL subparameter is an optional subparameter that is mutually exclusive with the L0VOLS and ML1VOLS parameters.

ALL

ALL specifies that all currently mounted ADDVOL ML1 and primary volumes be defined as the respective volume pools for aggregate recovery. Specifying the ALL parameter is equivalent to specifying the L0VOLS(*) and ML1VOLS(*) parameters. For this reason, do not specify the L0VOLS(*) parameter, the ML1VOLS(*) parameter, or both when you specify ALL.

The following subparameters are optional parameters that are mutually exclusive with the ALL subparameter. You can use one or both of the following parameters.

L0VOLS

L0VOLS(volser ...) specifies the list of volumes used as target volumes during recovery of nonmigrated non-SMS-managed data sets. If you specify a parameter of L0VOLS(*), all currently mounted ADDVOL primary volumes (up to 59) will be used as the primary volume pool for aggregate recovery.

ML1VOLS

ML1VOLS(volser ...) specifies the list of volumes as target volumes during recovery of migrated data sets to ML1 volumes. If you specify a parameter of ML1VOLS(*), all currently mounted ADDVOL ML1 volumes will be used as the ML1 volume pool for aggregate recovery.

Defaults: None.

Note:

If the DEFINE ARPOOL is issued without the ALL, ML1VOLS, and L0VOLS parameters, the aggregate recovery pool specified by agname is deleted. If an aggregate group name of * is issued without the ALL, M1VOLS, and L0VOLS parameters, the general pool of aggregate recovery volumes is deleted.
If a DEFINE ARPOOL command has not been issued when an ARECOVER command is issued, DFSMShsm uses all currently mounted ADDVOL primary and ML1 volumes as a temporary ARPOOL.
The L0VOLS in an ARPOOL are used to recover non-SMS-managed data sets. In an SMS environment, allocation is directed by the ACS routines. L0VOLS are used only in an SMS environment if the ACS routines do not direct allocation to any other volume.
You cannot define the same volume as both L0VOLS and ML1VOLS within a pool or between pools.
You cannot define SMS-managed volumes to an ARPOOL.
A volume previously added to DFSMShsm with the PRIMARY parameter of the ADDVOL command can subsequently be defined to the ARPOOL only by using the L0VOLS optional parameter.
A volume previously added to DFSMShsm with the ML1 parameter of the ADDVOL command can subsequently be defined to the ARPOOL only by using the ML1VOLS optional parameter.
Since the DEFINE ARPOOL command is only in effect for the duration of DFSMShsm startup, it is recommended that you add this command to the DFSMShsm parmlib member (ARCCMDxx) on the system that is the target of the aggregate recovery.
Do not allow the DEFINE ARPOOL to default to the current ADDVOL volumes for all aggregates. If you allow this, all aggregate recoveries will choose the same volume as target volumes, causing contention for those volumes. To reduce volume contention and to improve performance, it is more beneficial to define a unique set of volumes to each aggregate being recovered, especially if more than 1 ABARS address space is active simultaneously.