The primary volume for the couple data set. To ensure recovery, you should keep primary and alternate couple data sets on different volumes (volsers). Additionally, IBM recommends that backup or spare copies of the couple data sets be placed on a third volume.
Use a volume that has sufficient space and specify from 1 to 6 characters. Do not use SMS-managed volumes for the couple data sets.
Valid values: 1-6 characters, A-Z, 0-9, $, @, or #