IBM DS8000 manual Data Set FlashCopy, Incremental FlashCopy

Incremental FlashCopy

Write	Source	Target	Write
			Read
Read

Initial FlashCopy relationship established with change recording and persistent copy options

Control bitmap for each volume created

Incremental FlashCopy started

Tracks changed on the target are overwritten by the corresponding tracks from the source

Tracks changed on the source are copied to the target

Possible reverse operation, the target updates the source

Figure 7-2 Incremental FlashCopy

In the Incremental FlashCopy operations:

1.At first, you issue full FlashCopy with the change recording option. This option is for creating change recording bitmaps in the storage unit. The change recording bitmaps are used for recording the tracks which are changed on the source and target volumes after the last FlashCopy.

2.After creating the change recording bitmaps, Copy Services records the information for the updated tracks to the bitmaps. The FlashCopy relationship persists even if all of the tracks have been copied from the source to the target.

3.The next time you issue Incremental FlashCopy, Copy Services checks the change recording bitmaps and copies only the changed tracks to the target volumes. If some tracks on the target volumes are updated, these tracks are overwritten by the corresponding tracks from the source volume.

You can also issue incremental FlashCopy from the target volume to the source volumes with the reverse restore option. The reverse restore operation cannot be done unless the background copy in the original direction has finished.

Data Set FlashCopy

Data Set FlashCopy allows a FlashCopy of a data set in a zSeries environment.

Chapter 7. Copy Services 119