Setting RECATMIG to Y to recatalog ROLLED OF GDG during the archiving, all archived datasets are cataloged to MIGRATC VOLSER instead of ARCIVE. It is possible to have more explanation ?
Release : 12.5
Component : CA Disk Backup and Restore
Valid for ARCHIVE, BACKUP, DELETE, RESTORE, and RECOVER
When set to Y, archived data sets are cataloged to a volser of MIGRAT and a device type of X'C4C9E2D2' ('DISK'). Utilities like IDCAMS LISTCAT show the volser as MIGRAT with a device type of X'C4C9E2D2' (DISK). ISPF 3.4 volser field shows as MIGRAT2. Using MIGRAT allows CA Disk to maintain the DFSMS class constructs and Generation Data Set (GDS) status information in the catalog when an SMS data set is archived. By keeping the GDG status information, archived GDGs can be rolled out of the sphere and remain cataloged, depending on the GDG base attributes.
As far as the MIGRATC, ISPF is using a bit in the device type to determine where the data set is archived because HSM updates it to indicate ML1, ML2 or Cloud. Since CA DISK is used, the bit field matches Cloud.