A JES2 spool migration moves an existing JES2 spool volume (an extent or data set) to a new spool volume, or merges an existing volume with another existing spool volume. Migrating a spool volume to a new spool volume is called a move migration. Migrating a spool volume to an existing spool volume is called a merge migration. Both types of spool migration enhance JES2 spool configuration by providing the following functionality:

• Increasing or reducing the total number of spool volumes
• Increasing or reducing the size of spool volumes
• Extending volumes that have insufficient space to map all tracks
• Removing spool volumes without altering any spool pointers (MTTRs or MQTRs)
• Copying of data from one spool volume to another while address spaces are actively reading and writing data to the spool volumes
• Merging of volumes and track group map onto another spool volume
• Creating a new spool volume.