Managing Mirrored SQL Servers
Updated: November 1, 2013
Applies To: System Center 2012 - Data Protection Manager, System Center 2012 R2 Data Protection Manager, System Center 2012 SP1 - Data Protection Manager
System Center 2012 – Data Protection Manager (DPM) protects SQL Server databases and clusters that use SQL Server mirroring technology. This support does not translate into any major changes in the procedure to protect or recover SQL Server databases in DPM. The following sections will call out any changes in procedure.
Prerequisites to protect mirrored databases
Before you protect a mirrored SQL Server database, make sure that you meet the following prerequisites:
Install agents on both partners of the mirror.
Do not mirror the database on the same computer.
Protect a mirrored SQL Server database
The procedure to protect a mirrored database is the same as to protect a SQL Server database.
When you select a mirrored database to add to the protection group in the Create New Protection Group wizard, DPM automatically detects that the database is mirrored and displays the mirror details on the Select Group Members page.
Protect a mirrored SQL Server cluster
DPM also supports protection of mirrored SQL Server clusters. The procedure to protect SQL Server clusters that are mirrored is the same as to protect a mirrored SQL Server database.
|DPM agents must be installed on all the computers in the cluster.|
DPM protects all the following configurations:
Principal is clustered, mirror is not.
Principal is not clustered, mirror is.
Both principal and mirror are clustered.
A protected SQL Server database gets mirrored
At the time of backup, DPM will detect that the database was mirrored and will raise an alert. You will need to remove protection (with retain data) for the database, and then reprotect it.
|DPM will maintain a single replica for the mirror.|
A mirror is broken
When the mirror is broken for a mirrored SQL Server database that is currently protected by DPM, backups will fail with alerts. Remove protection (with retain data) for the SQL Server database and reprotect it.
Principal partner in a mirror fails over and fails back before the next backup
This scenario does not affect protection, because DPM is not informed about the fail over, unless a backup of the mirror is in progress.
Principal partner fails and the mirror server takes over
When DPM detects that the mirror is the principal partner, it stops the back-up job, and it performs a consistency check on the database that failed over after 30 minutes.
|If during these 30 minutes the database fails back to the original principal, DPM will detect this, and it will resume protection after performing a consistency check.|
If you try to back up the mirrored database before the scheduled consistency check (after 30 minutes), an alert that indicates that a consistency check is required will be created on the DPM Monitor tab, and the back-up will not start until a consistency check is done. To start the backup immediately, do a consistency check and retry the backup.
One protected database is made the mirror of another protected database
If one SQL Server database that is protected by DPM is made the mirror of another protected database, protection will fail for both partners of the mirror. To continue protection, you must protect the principal partner.
Recover a mirrored SQL Server database
When you recover a mirrored SQL Server database, always use the Recover to alternate location option. Even if you want to recover the database to the original location, use the alternate location option and provide the path to either of the partners of the mirror.
DPM does not support the following scenarios for mirrored SQL Server databases:
If the database is mirrored on the same server.
If the SQL Server mirroring session uses an explicitly configured IP address.
If the AlwaysOn feature in SQL Server 2012 is turned on.
For additional resources, see Information and Support for System Center 2012.
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