Q. Is SAN storage supported in Microsoft Exchange Server 2010?

A. This is a tricky one. In every Exchange 2010 document, you see direct attached storage (DAS) as the storage medium for Exchange 2010. This is for a number of reasons:

That's not to say you can't use a SAN for the storage of mailbox data. SANs still have advantages over DAS in terms of

If you already have a SAN or want to consolidate storage, then you can certainly use a SAN for the storage of Exchange 2010 databases. However, the key item is to make sure you'd don't have any single point of failure. You shouldn't have each Exchange server in a Database Availability Group (DAG) storing its replica of the database on the same SAN, as this makes the SAN a single point of failure (unless you have SAN replication going on behind the scenes).

Look at the messaging for Exchange 2010. Ideally, you should use DAGs with at least three copies of every database. That is a lot more storage and a lot more mail servers, and these servers will all be running enterprise editions of Windows and Exchange, which isn't cheap. The use of DAS over SAN helps offset the cost of additional hardware and licenses.

Many organizations may use the SAN for storage of one copy of the data and then DAS or another SAN for other copies. You can mix DAS and SAN.

Long story short, SAN is supported, but you need to make sure you don't make the SAN a single point of failure. When designing your storage, consider the points of failure, backup, and I/O.

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