VM /ETC

Posts Tagged ‘storage design’

Over the past few years I’ve been asked to troubleshoot and explain why cloning a virtual machine (VM) from a master template would take a longer time than expected more than once. Usually when I’m asked the virtualization admin is frustrated at the hypervisor. “This shouldn’t take this long. It needs to be fixed!” they say. “I definitely agree,” I say, “but let’s take a deeper look at what is happening here first before we flame the vendor’s help desk technician on the phone.”

So, this post is about taking a deeper look at where the master template VM resides versus where the cloned template is destined. My math my be a little off or may not account for every factor involved, but my point is to be close enough to demonstrate that the disk/array/LUN design is can be the culprit more times than not.

When I started this post I emailed for some help. I asked for a sanity check from some storage experts. I’ve been reasonably happy with my own answer until now, but I figured I do some research before adding the content to VM /ETC. I got back a single reply that I am paraphrasing: “Sounds about right. Let me think about it some more and if I can stump you with anything else I’ll let you know.” He never did so I’ll take that as a positive confirmation meaning “yes VM moron, it is that simple.” Good enough for me! If anyone can point out any other factors I am not properly accounting for please leave a comment.

The following is part of my email for help. It not only explains my test scenario but it illustrates the problem and resolution as well. At the end of this post I make some suggestions for bettering the time it takes to clone a VM.

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