The OPC(One Point Copy) function of ETERNUS Disk storage system is used to copy data from a transaction volume to an unused backup volume.
To perform a snapshot fast backup, take the following steps:
When swstbackup (Backup execution command) is executed ((1) in the following figure), an unused backup volume with the same size as the relevant transaction volume is selected from the unused backup volume management area.
If the number of backup volumes exceeds the number of preservation generations by performing backup, the history of the oldest backup volume is deleted, and then the volume is selected as an unused backup volume.
Data on the transaction volume will be copied to the selected unused backup volume. The logical copy is instantly performed and the physical copy is started on the hardware ((2) to (4) in the following figure).
Backup carrier information will be set.
Figure 3.2 Snapshot fast backup processing
The snapshot fast backup is completed as soon as you confirm the execution of the backup. The actual data copying will be performed internally by the OPC function of ETERNUS Disk storage system.
The QuickOPC function of the snapshot high-speed backup creates a snapshot image by only copying the data updated since the start of previous backup. This reduces the time for physical copying significantly.
For information on the QuickOPC function, refer to "Chapter 5 Backup Operation using QuickOPC Function".
Note
If all the generations of backup volumes are being managed, and if no backup volume can be obtained from the unused region in the backup volume management area, backup copies cannot be created.
