HP Application Recovery Manager software A.06.10 Administrator's guide (March 2008)

Advantages
• Restore is very fast, regardless of the amount of data that was backed up.
• The old source volumes can be retained after restore.
Disadvantages
• It is not possible to perform another restore from the same backup.
• If a replica to be restored belongs to a different disk group than its source volumes,
the disk group of the replica becomes the disk group of the source volumes after
instant recovery. In this case, depending on the target disk group characteristics,
the source storage volume performance may decrease.
• Redundancy level (RAID) of the source storage volumes can decrease if the replica
to be restored has a lower redundancy level.
To perform this type of restore, select the option Switch to the replica in the Application
Recovery Manager GUI.
Copying replica data and retaining the source volume
With this method, a new copy from a replica is created in the same disk group in
which the source storage volume reside. The procedure is the same as creating a
new snapclone replica during backup. When the copy is finished, a switch of disks
between the source volumes and the new copy is performed. The old source volumes
are retained.
The replica is also retained in the replica set and another instant recovery is possible
from the same session.
Advantages
• The old source volumes are retained after restore.
• The performance characteristics of the restored volumes remain the same. This is
because the physical disks and the characteristics of the source storage volumes
(size, RAID level) do not change.
• Another restore from the same backup is possible.
Disadvantages
• Restore is not as fast as with the "switching disks" method.
• Restore requires additional storage space in the disk group of the source volumes.
To perform this type of restore, select the options Copy replica data to the source
location and Retain source for forensics in the Application Recovery Manager GUI.
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