System Programmer Reference › Backing Up Data › Backup Formats › CMS Backups

CMS Backups

When backing up data in CMS format, CA VM:Backup uses the CMS file directory to determine which files to back up and backs up the CMS minidisks by file. If you specify a CMS backup, CA VM:Backup backs up data using CMS format unless the minidisk:

• Has been recomputed; in this case CA VM:Backup backs up the CMS area of recomputed minidisks by file and backs up the recomputed area physically
• Is reserved; in this case CA VM:Backup backs up CMS-reserved minidisks physically
• Is a non-CMS minidisk; in this case CA VM:Backup does not back up the minidisk

Data backed up using CMS format is device-independent when it is restored; you can restore files backed up from one CMS-supported DASD device to any other CMS-supported DASD device. This allows easy migration of older DASD devices when new DASD types are introduced. Reserved and recomputed areas backed up physically are device-dependent when restored. For more information, see Physical Backups.

For more information about CMS-reserved minidisks and recomputed portions of minidisks, see Backing Up Special CMS Minidisks.