Take Five With Tom Fenton

5 Questions About Virtual Volumes for Your Vendor

VVOLs are a breakthrough for virtual environments, but every storage vendor handles them differently.

vSphere Virtual Volumes (VVOLs) is one of the hot topics in virtualization right now. Many articles have been written on the architecture and mechanisms of VVOLs; the issue now is that we need to understand how the various vendors are implementing VVOLs.

A key VVOLs point to is that it's just a framework for virtual machine (VM) storage. Each array can surface different capabilities up from their arrays to vSphere. Because of that, I've been amazed to see how differently vendors are using VVOLs.

With that in mind, here are five talking points to begin your discussion with your storage vendor around its implementation of VVOLs.

  1. When will your arrays support VVOLs, and what models will support them? The reason for asking this is that some vendors are offering Day 1 support for VVOLs on all their arrays, while others will deliver them on a subset of their product line over time.
  2. What will it take to upgrade my array to be VVOLs-capable? Related questions you should ask include: Will I need to update my firmware or my hardware? Will I need to deploy a VVOLs gateway? Will I be able to do this non-disruptively, or will I need to suffer an outage? Is VVOLs an additional feature or is the price inclusive? 
  3. What capabilities will be surfaced up? This is important to know since different vendors will surface up different capabilities. All the VVOLs implementations I've investigated so far do instant snapshots and clones; however, some vendors offer differentiators such as encryption and charge back; some even offer quality of service features.
  4. How well will the capabilities perform? It's one thing to offer a capability, but quite another for the capability to perform well. Since VVOLs aren't a panacea for poorly performing arrays, chances are that if an array didn't perform well in your environment before the vendor implemented VVOLs, it will perform poorly with VVOLs. However, the converse isn't necessarily true: if an array performs well without VVOLs, this doesn't necessarily imply that the same array will work well with VVOLs. Trust but verify, either on your own or through a trusted source.
  5. How user-friendly will the capabilities be? This is a highly subjective question, and you should ask to see a live demonstration of the array in action, or have the vendor provide third-party validation of any claims made regarding ease of use.

These are just a start of the questions you should be asking your vendor when initiating your VVOLs discussion. The first three questions can easily be answered by the array vendors themselves. However, questions four and five are more subjective. The company I work for (The Taneja Group) will also be working with various vendors to investigate them further.

About the Author

Tom Fenton works in VMware's Education department as a Senior Course Developer. He has a wealth of hands-on IT experience gained over the past 20 years in a variety of technologies, with the past 10 years focused on virtualization and storage. Before re-joining VMware, Tom was a Senior Validation Engineer with The Taneja Group, were he headed their Validation Service Lab and was instrumental in starting up its vSphere Virtual Volumes practice. He's on Twitter @vDoppler.

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