I put two questions in my title. If you think I should split them, please comment.

We pay for a dedicated server and I saw that my harddrive was vda1, so that started me looking. My host explained that they have virtualized our server to make deployment / redeployment faster. This leads me to 2 important questions.

  1. How can I prove (or disprove) that our VM is the only one on the host? (This is the most important question to me a the moment.)
  2. If we are the only VM on the box, will the virtualization slow down the server?

I thought of asking my host to give me shell access to the host, but I don't know enough Linux to get in there and really understand what I'm seeing.

  • 2
    1) You can't. 2) is now immaterial. – MadHatter Sep 19 '13 at 16:05
  • When you say that you pay for a "dedicated" server are you saying that you're paying for a dedicated physical server or is it a VM on a dedicated physical server? Allocating a dedicated physical server for every dedicated virtual server will not scale and I doubt that your provider is doing that. You need clarification on what "dedicated" means from your provider. – joeqwerty Sep 19 '13 at 16:48
  • @joeqwerty In the past, we always had a physical box that was all our own. Our server was recently migrated to the Provo UT datacenter that was in the news recently for some really slow response times across the entire datacenter. I think that during the move over there is when they put us on a VM. They say it's a single VM on the one physical server just to help speed deployment. – TecBrat Sep 19 '13 at 17:05
  1. The only way to prove or disprove this is to have access to the host machine, aka the hypervisor.

  2. Theoretically, virtualization does have an effect on performance, even if there is only one VM on the host, versus running code directly on the physical machine's hardware. But exactly how much of an impact depends on many factors, and can only be measured through comparative benchmarks.

You might be able to speculate that there are other VMs sharing the same host with you if you have access to some sort of performance counter in your guest OS like CPU Steal Time, etc., but that is hypervisor and operating-system specific.

If you are paying for a dedicated physical machine and you suspect that your hosting company is trying to pull a fast one on you, then you have to take that up with your hosting provider.

  • I looked and found that CPU Steal Time is reported at the top of top. (Summary window) and It held steady at 0.0% so it would suggest that ours IS the only VM running, or that at least there's no competition for CPU cycles at the moment. Thanks for that suggestions. – TecBrat Sep 19 '13 at 17:02

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