How SnapManager Restore works

SnapManager Restore performs a sequence of steps when it restores a backup copy. If you are restoring in a Windows cluster, do not attempt to manage any cluster resources while the restore operation is running.

Checks that the backup copy is verified.
If not, SnapManager checks if you have enabled the Database Verification Override option and continues.

Attention: You must restore only from verified backup copies to ensure a successful restore operation.
Creates a Snapshot copy of the volume to be restored, so that the state before the restore operation is preserved.
Restores the data from the Snapshot copy of the LUN to be restored.
Restores the transaction logs that you need to replay to restore the data.
Uses the Exchange recovery process to play these transaction logs to the restored databases.
On Windows Server 2003, the soft recovery process is used, which is a transaction log replay process that occurs when a database is re-mounted after an unexpected stop, or when transaction logs are replayed into an offline backup of a database.

How to choose the type of restore operation to perform
You should consider your reasons for performing a restore operation so that you can decide what type of restore operation to perform: point-in-time or up-to-the-minute restore operation.
Types of SnapManager Restore operations
There are two types of SnapManager Restore operations. In a point-in-time restore operation, the transaction logs in the active file system not committed to the databases at the time of backup operation are replayed. In an up-to-the-minute restore operation, all uncommitted transaction logs are replayed and are applied to the databases. This option is selected by default.
Snapshot copies created during a restore process
Every time you perform a restore process, a Snapshot copy is created on the volume that contains the transaction logs.
Methods that can decrease restore process time
You can decrease the time that SnapManager requires to complete a restore operation by making more backup copies and ensuring that any LUN clone split operations in progress are complete.
Transaction log sequence verification options
You can make a restore operation faster by omitting the pre-restore transaction log sequence and database metadata checks. However, if you omit these checks, and a problem exists with your transaction log sequencing or your database metadata, the restore operation fails.
LUN Clone Split Restore method
SnapDrive uses the LUN Clone Split Restore method for Data ONTAP 7.1 or later. This feature enables you to perform a restore operation quickly, because the only data blocks that are duplicated during the restore operation are those currently in use in the active file system.
SnapManager Restore in a Windows cluster
In a Windows cluster, SnapManager does not take the entire Exchange virtual server offline; instead, it takes the online Storage Group that is to be restored offline before performing a restore operation. SnapManager takes the Storage Group that is to be restored offline before performing the restore process, if that Storage Group is still online.
SnapManager Restore in a live Exchange virtual server cluster
SnapManager can restore databases in a clustered Exchange virtual server while keeping the cluster physical disk resource or the Exchange virtual server online. Keeping the cluster physical disk resource or the Exchange virtual server online minimizes downtime during the restore operation for databases in Storage Groups that share a cluster group but are not being restored.

Parent topic: Database restore operation using SnapManager