A short write-up after some recent articles which were published to clarify and emphasize Microsoft’s current position on virtualization and the support for storing Exchange information on NFS volumes. I will stick to the headlines, as the topic has already been touched several times by people from the Exchange community, after which I would mostly be repeating things that have already been said. Yet, many customers still have the perception that Exchange on NFS is supported or are actually running this configuration, often the result of a push from the storage or virtualization vendor. As it is not, I will repeat key information here to counter misleading information, hoping it might prevent customers from selecting unsupported configurations.
End of last year, a lively discussion was revived on some distribution lists and forums on why NFS was still not supported for storing Exchange information. However, it was all speculation as the creator of the product did not take part. The official support statement was (and is) that Exchange is not supported on NFS and only block-level storage is supported. Tony Redmond did a write-up on that here.
Then, in the preamble of the Microsoft Exchange Conference 2014, a ‘suggestion’ to support NFS was put on the community ideascale site, where people can propose suggestions for Exchange. This site is not an official channel but it does provide a way for the community to gather suggestions and check for demand. So, it allowed to verify if the current lack of NFS support was major thing or not, as people producing the most noise do not necessarily represent the majority. Response seemed limited, except for some hardware vendors who made lots of noise, possibly in an attempt to get traction in the Exchange community.
Then, Tony did a follow-up article after a discussion with Jeff Mealiffe, knowledgeable on Exchange, Sizing and Virtualization and nicknamed ‘The PerfGuy’ for obvious reasons. In the article, the problem areas of NFS are set out. Interestingly (but not surprising), Exchange is similar to SQL Server from a storage perspective, the latter having very specific documentation regarding storage requirements. Also mentioned is that successfully running JetStress by the vendor is no indication on the supportability of storage configurations. After all, that JetStress succesfully runs for a certain amount of hours is great, but it is a storage performance validation tool, not a storage supportability validation tool. At the Microsoft Exchange Conference 2014, using arguments presented earlier in the article, Jeff reaffirmed the non-support of NFS in his presentation.
The discussion seemed to die down until few weeks ago when Tony was in a Twitter conversation with one Josh Odgers, engineer at one of the storage vendors. In the discussion Odgers dropped the rationale and even went so far as to insult people. When searching online, you will find other rants as well, so I guess Josh’ employer does not have any form of social media guidelines for their employees. That does not help when you are trying to lobby for your cause (and potential markets for your storage appliances). Tony wrote an extensive response here, I recommend checking it out.
Now what storage vendors and their employees do or do not do is up to them. However, things like this may become an issue when vendors repeatingly and knowingly position their storage solution as a supported alternative to customers, like for example Odgers does for Nutanix (NDFS is Nutanix’ proprietary distributed NFS implementation). Yes, I’m sure it flies like a rocket and I am sure some customers will be persuaded by sales people to a game of chance by running Exchange on their appliances. As an Exchange consultant however, I prefer supported solutions and so should you. Or have a serious chat with the Risk Manager.
Update (Jul 9,2014): The UC Architects fellow Mahmoud Magdy posted a blog on his experiences and encountered limitations of storage appliances such as Nutanix here.