Systems support defines the availability of a volume set with the AVAILABILITY operand in the MODIFY-PUBSET-DEFINITION-FILE command. Possible values are STD and HIGH. In this case the system does not check whether the actual property of the volume set matches the assigned values. It is up to systems support to select values which correspond to reality.
The availability value assigned by systems support corresponds to the long-term positioning which was intended for the volume set within the SM pubset. Changing the AVAILABILITY value from HIGH to STD requires considerable organizational effort as particularly the files on the volume set with the file attribute AVAILABILITY=*HIGH must first be moved to another volume set with high availability.
The availability of a volume set can be enhanced, for instance, by using a suitable RAID level in the disk storage system (RAID 1/0, RAID6) or volume mirroring.