Exchange Server 2010 : Deploying a Database Availability Group (part 2) - Suspending and Reseeding a Database

Suspending and Reseeding a Database

In the event that a replica of a mailbox database should become out of sync with the primary copy, it becomes necessary to reseed the database in order to resume the replication of log files. There are a few situations that can cause the need to sync the databases:

• Bringing a replica back online after extended downtime

• Corruption of log files

• Corruption of a database

• An extended WAN outage

The easiest way to determine if a database needs to be resynchronized is to look at its current replication status:

1.	Launch Exchange Management Console.
2.	Expand Organization Configuration.
3.	Click Mailbox.
4.	In the middle pane, click the Database Management tab.
5.	Click the database whose replication status you want to check.
6.	In the lower pane, look at the Copy Status on the replicas in question. If they are in a Failed state, they will likely need to be reseeded.

Note

If you have a large number of mailbox databases, it may behoove you to take advantage of the filter function. This allows you to match based on Master, Mounted, Mounted on Server or Name. You can use the browse button to look for specific Exchange Server names to match against.

If the database is found to be in a failed state, it can be reseeded in the following manner:

1.	Launch Exchange Management Console.
2.	Expand Organization Configuration.
3.	Click Mailbox.
4.	In the middle pane, click the Database Management tab.
5.	Click the database whose replication status you wish to fix.
6.	In the lower pane, click the database replica that is in a failed state.
7.	Right-click the database and select Suspend Database Copy. Enter an optional comment if you want, then click Yes.
8.	The Copy Status should update to read Suspended (see Figure 7). Figure 7. Viewing the Summary Copy Status.
9.	Right-click the suspended database and select Update Database Copy.
10.	Enter a hostname to specify which cluster networks should be used for seeding (see Figure 8). Click Add. Figure 8. Updating the database copy.
11.	Click Update.
12.	The update might take a while depending on how big the database is and how many log files have been created since the database was last in sync (see Figure 9). Figure 9. Checking status of the Update Database Copy Wizard.
13.	When the wizard finishes, click Finish.
14.	Refresh the view in EMC, and the database should now have a status of Healthy (see Figure 10). Figure 10. Viewing the Summary Copy Status.

The same process of suspending and updating the Database Copy can be performed via Powershell:

1. Launch Exchange Management Shell.

2. Type Suspend-MailboxDatabaseCopy–Identity DatabaseName\ReplicaServer where DatabaseName and ReplicaServer are the names of the DB you want to update and the server holding the replica that is to be reseeded. Answer Yes when prompted.

3. Type Update-MailboxDatabaseCopy–Identity DatabaseName\ReplicaServer–DeleteExistingFiles. Answer Yes when prompted (see Figure 11).

   Figure 11. Updating from Exchange Management Shell.