SQL Database mirroring with failover clustering for SharePoint 2010

I was asked a question in my previous post on my High Availability Options for SharePoint. I thought it would be good to share this as a seperate post.

The question was:

How can I implement both solutions? (Database Mirroring & SQL Clustering)

Clustering (active\passive) – For prevention of hardware failure.
[Mirroring] – For prevention of clustered shared storage failure.

My answer:

There are a few different scenarios or ‘modes’ that you can consider if you plan on implementing both solutions at the same time.

1. High-Safety mode Session with Automatic Failover

– Principal on active node in Cluster A.

– Mirror on another clustered node on Cluster B or standalone box.

– Requires a witness server- Synchronous database mirroring

– When cluster failover takes place, the mirror becomes the principal in Cluster B.

– When the passive node in Cluster A becomes active, it becomes the new mirror.

– You can fail back and forth.


2. High-Safety Mode Session Without Automatic Failover

– Same scenario above except not automatic failover with database mirroring.

– No witness server required

– Requires manual intervention to failover database mirroring.

– Synchronous database mirroring


3. High-Performance Mode Session

– Database mirroring Principal will be on the failover clustered instance.

– If cluster fails, the mirror can be activated.


You also must consider the following:

– Assess your environment. Will it support Clustering?

– Assess your shared Storage capabilities – may consider SAN replication or virtual storage.

– These solutions WILL require additional storage, so check on your storage capacity.

– Clustering over geographical distances.. i.e. two data centres – latency, bandwidth?

– Mirroring over geographical distances – latency?
For more information: http://msdn.microsoft.com/en-us/library/ms191309(v=sql.100).aspx

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