Incremental system-level backups

You can use the BACKUP SYSTEM utility to take incremental FlashCopy® backups of the data of a non-data sharing Db2 subsystem or a Db2 data sharing group. All of the Db2 data sets must reside on volumes that are managed by DFSMSsms.

An incremental FlashCopy relationship is established for each source volume in the copy pool with corresponding target volumes. Multiple incremental FlashCopy backup versions are supported.

The following BACKUP SYSTEM utility keywords support this feature:

ESTABLISH FCINCREMENTAL: Specifies that a persistent incremental FlashCopy relationship is to be established, if none exists for source copy volumes in the database copy pool. Use this keyword once to establish the persistent incremental FlashCopy relationships. Subsequent invocations of BACKUP SYSTEM (without this keyword) will automatically process the persistent incremental FlashCopy relationship.
When ESTABLISH FCINCREMENTAL is specified, the system-level backup is recorded as an incremental copy backup in Db2 and in DFSMShsm because an incremental FlashCopy relationship has been established for the backup disk version.
END FCINCREMENTAL: Specifies that a last incremental FlashCopy backup be taken, and for the persistent incremental FlashCopy relationship to be withdrawn for all of the volumes in the database copy pool. Use this keyword only if you do not need additional incremental FlashCopy backups of the database copy pool.
When END FCINCREMENTAL is specified, the system-level backup is recorded as a full copy backup in Db2 and in DFSMShsm because the backup disk version no longer has incremental FlashCopy relationships.

The first time that you use the ESTABLISH FCINCREMENTAL keyword in an invocation of the BACKUP SYSTEM utility the persistent incremental FlashCopy relationship is established. The incremental FlashCopy relationship exists until you withdraw it by specifying the END FCINCREMENTAL keyword in the utility control statement.

For the first invocation of BACKUP SYSTEM that specifies the ESTABLISH FCINCREMENTAL keyword, all of the tracks of each source volume are copied to their corresponding target volumes. For subsequent BACKUP SYSTEM requests, only the changed tracks are copied to the target volumes.

If you keep more than one DASD FlashCopy version of the database copy pool, you need to create full-copy backups for versions other than the incremental version.

For example, you decide to keep two DASD FlashCopy versions of your database copy pool. You invoke the BACKUP SYSTEM utility with the ESTABLISH FCINCREMENTAL keyword. A full-copy of each volume is created, because the incremental FlashCopy relationship is established for the first time. You invoke the BACKUP SYSTEM utility the next day. This request creates the second version of the backup. This version is a full-copy backup, because the incremental FlashCopy relationship is established with the target volumes in the first version. The following day you run the BACKUP SYSTEM utility again, but without the ESTABLISH FCINCREMENTAL keyword. The incremental version is the oldest version, so the incremental version is used for the FlashCopy backup. This time only the tracks that have changed are copied. The result is a complete copy of the source volume.

DFSMShsm supports multiple versions of FlashCopy backups for a copy pool.