Moving and merging spool volumes

The $MSPL command migrates JES2 spool volumes. The command moves a source spool volume to a new target spool volume, or merges two existing spool volumes. Source and target spool volumes are specified by their volume serial numbers (volsers). When migrating to a new spool volume, the command can also format the new volume, allocate space, and create data sets. See $MSPL - Migrate spool volumes for complete command usage details.

Moving a spool data set from an existing volume to a new volume allows you to change the size of the spool data set. If the new volume has a spool data set, that data set is used. Otherwise, a new data set is created, or allocated, according to the SPACE= keyword that was specified using the $MSPL command. If the new data set is smaller than the existing data set, the space that is being removed cannot be allocated. If the space being deleted is in use, the move migration will fail.

Merging an existing spool volume (extent or data set) with another existing spool volume also changes the size of the spool extents or data sets. To merge volumes, the target spool volume must have a contiguous free area that is at least as large as the used area in the source volume. For example, merging SPOOL1 onto SPOOL2 maps and copies the used space from SPOOL1 onto SPOOL2. Once completed, the spool data set on SPOOL1 is unallocated, and the DASD is no longer in use by JES2. However, the extent ($DAS) for SPOOL1 still exists and can be displayed with a special MAPPED status by the command $DSPOOL(SPOOL1)

Figure 1 represents a merge migration, which is a JES2 spool volume being merged with another existing JES2 spool volume. The target volume must have enough available free space to support the merge. Once completed successfully, the source spool volume is no longer an allocatable spool volume.

Figure 1. Merge migration

Following a successful spool migration, the source spool volume is no longer recognized as an allocatable spool volume. All JES2 processing has been completed or purged from the source volume. For a move migration, the source volume is now on the new spool volume. For a merge migration, the source volume is now on the specified existing spool volume. The target spool volume has the complete data set from the source volume on it, including any tracks that were written to the source during the active migration.

The following example shows output from a successful merge migration:

$mspl(spool1),target=spool2 

$HASP893 VOLUME(SPOOL1) 
$HASP893 VOLUME(SPOOL1)  STATUS=MIGRATING-MERGE,AWAITING(MIGRATION),
$HASP893                 TARGET=SPOOL2 
$HASP646 0.7489 PERCENT SPOOL UTILIZATION 
$HASP808 Migration of SOURCE=SPOOL1 volume to TARGET=SPOOL2 volume
RC=9 -- Migration INITIALIZING phase started.
$HASP808 Migration of SOURCE=SPOOL1 volume to TARGET=SPOOL2 volume
RC=33 -- Active migration completed successfully

Table 1 summarizes the limitations to consider when choosing between a spool move migration and a spool merge migration:

Table 1. Limitations on move and merge migrations. This table summarizes the limitations that apply to spool move and merge migrations. An X character indicates that the limitation applies to the type of migration. The N/A characters indicate that the limitation does not apply to the type of migration.
Limitation	Move migration	Merge migration
The Source spool volume must be INACTIVE.	YES	NO
The Target spool volume must be ACTIVE.	NO	YES
The number of records per track on the Source spool volume must be less than or equal to number of records per track on the Target spool volume.	YES	YES
The Target spool volume must support the largeDS settings on the Source spool volume.	YES	NO
The number of tracks per track group is inherited from the Source spool volume.	YES	NO
The Source spool volume cannot use absolute addressing.	YES	NO
The Target spool volume cannot use absolute addressing.	YES	YES