The Equivalent Copy (EC) or The Remote Equivalent Copy (REC) function of the Fujitsu ETERNUS storage system is used to copy data from a transaction volume to an unused backup volume. Backup data is then copied from the backup volume to tape.
Synchronous high-speed backup is performed as follows:
When "11.2.2.11 acmstartsync (Synchronous backup start command)" is executed (Step 1 in the figure below, "Synchronous high-speed backup processing"), an unused backup volume with the same size as the relevant transaction volume is selected from the unused backup volume management area and backup synchronous processing begins.
The transaction and backup volumes are both placed in equivalency maintenance status. From this point on, equivalence between the transaction volume and backup volume is maintained. This status is referred to as the equivalency maintenance status (Step 3 in the figure below, "Synchronous high-speed backup processing").
When "11.2.2.1 acmbackup (Backup command)" is executed (Step 4 in the figure below, "Synchronous high-speed backup processing"), backup synchronous processing stops and copy from the backup volume to tape begins. Backup history information is set.
If backup volumes under generation management exist for all the generations when backup has been completed, the oldest backup volume is treated as an unused backup volume.
Note
"11.2.2.1 acmbackup (Backup command)" cannot be executed before the transaction and backup volumes have become equivalent.
Figure 5.4 Synchronous high-speed backup processing
The command completion timing can be selected from the history created in either the disk backup history information or the tape backup history information using the relevant option.
During synchronous high-speed backup using the Suspend/Resume function, the equivalency maintenance status of EC can be set to Suspend or Resume. Consequently, the synchronous backup process can be made faster because the function can create a differential copy from the Suspend state.
For more information on the Suspend/Resume function, refer "5.1.3 Backup processing using the Suspend/Resume function".
Note
If all generations of backup volumes are managed, and if no backup volume can be obtained from the unused region in the backup volume management area, backup copies cannot be created.
The backup function which used REC/ROPC is restricted to the ETERNUS storage systems corresponding to REC/ROPC in the same Storage Server.
