Everyday Virtualization

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Religious Issue No. 9: NFS, iSCSI or Fibre Channel

As an administrator, one of the best things I can do is always compare what I am doing to what someone else is doing. This allows me to broaden my perspective and have answers for virtually every scenario that can arise in administering a virtual infrastructure. In the course of reading a quality blog post by Scott Lowe, I found myself with a blog post of my own for the same topic.

In Scott's piece, he focuses on NFS for use with VMware environments. In fact, I candidly sought out Scott earlier in the year to see how many implementations actually use NFS. I'm a big fan of vStorage VMFS, so before I swore off NFS, I wanted to quantify where it stood in the market. Scott's comments echoed that of readers here at the Everyday Virtualization blog, as well. NFS is quite prevalent in the market for VMware implementations.

So, with Scott's material and reader interest, I thought it a great time to share my thoughts on the matter. My central point is that above all, there needs to be a clear delineation of what the storage system will serve. I see this breaking down into these main questions:

  • Will the storage system be provided only for a virtualization environment?
  • Does the collective IT organization have other systems that require SAN space?
  • Will tiers of storage be utilized?
  • Who will manage the storage -- virtualization administrators or storage administrators?

If these questions can be answered, a general direction can be charted out to determine what storage protocol makes the most sense for an implementation. In my experience, virtual environments are a big fish in a pool of big storage -- but definitely not the only game in town.

If the storage is not directly administered by the virtualization administrators, the opportunity to decide the storage protocol can be limited.

There are so many factors including cost, supported platforms and equipment, what's already in place, performance, administration requirements, and other factors that make it impossible to make a blanket recommendation. I'd nudge you the direction of iSCSI or fibre channel so you could take advantage of the vStorage VMFS file system. NFS will likely have the lowest cost options, as well as the potential for the broadest offerings of storage devices, to its credit.

What factors go into determining your storage environment? My experience is that heterogeneous systems that require SAN space can be aggregated to one SAN, and that generally falls up to a fibre channel environment. Share your thoughts on factors that decide the storage protocol for a virtual implementation.

Posted by Rick Vanover on 07/06/2009 at 12:47 PM


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