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Chapter 3 Notes
75
(3) Restoration and Data Consistency
When restoring data upon failure on MV of business server, backup data existing on tape is
utilized in the following operations:
(i) From backup server, restore data on MV that is connected to business server via network.
(ii) If tape device is connected to business server, restore data from tape to MV directly.
(iii) Restore data on RV upon backup server, and synchronize MV with RV using the restoration
function of data replication.
When restoring master volume data with operation (i) or (ii), data is restored with the standard
function of backup software, just as the backup operation without data replication.
When restoring master volume data with operation (iii), the static points on both business server
and backup server must be specified. Maintain data consistency in the following procedures.
The processes are applicable also when using RV itself as a backup medium.
On business server
Deletion of partition or discarding of cache data is required on business server.
To discard cache data, flush the MV cache data and unmount the MV using the commands
provided by replication operation. You can use the -force option to forcibly unmount the MV
even when the file system is being used.
If the process above is omitted, inconsistency may occur between cache and volume upon
separating again, which may result in destruction of file system.
On backup server
Primarily, temporarily halt the operations on the RV, and flush the cache data and unmount the
RV using the commands provided by replication operation to release the association between the
file system and disks.
(4) Restoring file system
If MV is separated RV without releasing association between file system and disk on volume used
on MV, access to volume on RV may result in displaying an error message and use of RV is
disabled. In such a case, execution of CHKDSK command on the accessing volume removes file
system inconsistency. Refer to CHKDSK help before using the CHKDSK command.