The SANity of Using Networked Storage Rather than DAS for Exchange and SQL

May 4, 2010

in 2010, Exchange, Microsoft

Commissioned by EMC and is distributed under license from ESG, this recently released white paper by Mark Peters includes topics on the Current Market Situation, Options and Opportunities, Implementation Considerations and the Bigger Truth as they relate to networked storage and direct attached storage (DAS).


Beginning with a brief discussion of the current market situation, Mark discusses the decades old IT trend of the replacement of rigid DAS systems with a more flexible storage architecture.  Mark makes special note how this trend is very strong in virtual server environments.   Despite the strong encouragement from Microsoft to run Exchange 2010 on DAS, almost two thirds of the leading edge adopters of Exchange 2010 are favoring networked storage over DAS.  There are clear advantages that Microsoft gains by pushing DAS over NAS/SAN, citing tighter integration, lower costs and improved application performance.  As Mark is quick to point out, this all comes at a cost of flexibility and management.  IT administrators could quickly find themselves in a situation where they are managing dozens (if not hundreds) of independent and isolated storage platforms.  If more capacity is needed, free space from another server cannot be used resulting in poor storage utilization.  Backup and DR operations need to be executed and monitored on individual servers.  Microsoft specific tools such as VSS are free, but are traditionally suited for simple environments with few servers and minimal storage capacity as they too are configured on a per device basis.  It’s no secret that Microsoft has made great strides in reducing the IO load that Exchange 2010 places upon storage, which Microsoft states can make DAS more relevant, but it can be easily argued that this makes it easier to benefit from the many other advantages that a network storage model provides.  Networked storage devices can benefit the entire data center and business including, but not limited to, Exchange and SQL.  Such areas of improvements can be seen in TCO, capacity utilization, scalability, management, high availability, disaster recovery, backup and recovery and server virtualization.

Exchange and SQL are often business critical applications and their underlying infrastructure should reflect that.  In the holistic sense of making progress, networked storage can be an engine whereas DAS can all too easily become an anchor.  The job of IT is to deliver business value, whether that’s measured as minimizing cost, maximizing agility or reducing risk.

Click here to download the white paper…

Regardless of your opinion on the subject, the white paper is a good read and provides some good food for thought when the time comes for a decision to be made on the storage platform for your Exchange 2010 architecture.  I hold high praise for the Exchange product team, especially those working on the ESE engine and their hard efforts to reduce the IO load of Exchange.  I welcome the additional storage choices available to Exchange 2010. As Mark points out, there are many factors that should be considered when choosing your storage platform for your Exchange architecture.  Consult your vendors, ask questions and read between the lines.  If you are overwhelmed with options and don’t know which way to go, get help.  It’s a immeasurably cheaper in the long run to start your design with a solid foundation than have to change gears a year into the project.  Just because you can use DAS, doesn’t mean that it’s best for your business model.

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