Category Archives: Cluster

When will my replica be synchronized?

Recently, I was pulled into a gig to help troubleshoot an windows failover cluster service issue that was hindering an availability group. Just to give a little background information its a two node windows cluster with two replicas the availability groups are using synchronous mirroring. Once, this was resolved we had a critical database that was behind on synchronization because one of the two replicas (cluster node) was down. This lead to the following question. When will my replica by synchronized?

This question was easy to answer with database mirroring. We could pull up the database mirroring monitor. We don’t have an database replica monitor GUI tool built into SSMS. Lucky for us, its not that hard with availability groups. We just have to use performance monitor. You will see below there is an perfmon collection called “SQLServer:Database Replica” that comes in handy for us.

When will replica be synchronized?

When will replica be synchronized?

Above, you can see that this secondary replica which is back online is synchronizing as its receiving log bytes and the Recovery Queue shown in the performance monitor is also reducing as the synchronization process is catching up. According to MSDN Recovery Queue is the Amount of log records in the log files of the secondary replica that has not yet been redone.

Move the Quorum Disk Group

Recently, I worked on a project to migrate data from a four node cluster (3 active, 1 Passive) from an old SAN to a new SAN using SAN Copy by EMC. Once, the data was copied I failed the services around and verified that each service would work on each node. Here is how I moved the quorum disk to each node.

To move the quorum disk group you have to run the command listed below in the command prompt. Make sure you run the command prompt with Administrator rights or you might see an access is denied error.

Cluster group “Cluster Group” /move:<newnode>

If the cluster disk group was active on the db1 node and you wanted to migrate the group to db2 you would use the command below in the command prompt.

Cluster group “Cluster Group” /move:db2

If you like this post check out  my post on renaming the server name for a SQL Cluster or my other cluster posts.