[Users] openvz disk access performance

[Kirill Korotaev]

If someone is interested in doing a 3rd party comparison I can help with the
correct methodology creation taking into account lots of obstacles such as
disk non-uniform performance, not always real time ticking inside VMs and so
on. It's really really hard to make an apples to apples comparison :(

Kirill

On 1/19/09 11:23 PM, "Michael H. Warfield" <mhw at wittsend.com> wrote:

> On Mon, 2009-01-19 at 14:49 -0500, openvz.org at jks.tupari.net wrote:
>> According to
>> http://www.scribd.com/doc/4916478/comparison-of-open-source-virtualization-te
>> chnology
>> openvz has good network performance, but bad disk access performance.  Has
>> anything changed in the 4 months since that was posted?
> 
>         Wow...  Could they possibly chosen a more inconvenient format.  A
> slide
> show in pdf fed through flash.  That was painful.  Can't even download
> the pdf to just page through it without signing up for an account.  Man
> that sucks.
> 
>         I'd like to see some independent validation of those numbers and the
> methodology.  Some things in there don't seem to pass the smell test
> (particularly wrt disk times) and I wonder how well managed things like
> file system positioning (location within a disk) and fragmentation were
> managed and controlled.  I would like to know if they ran each test from
> a controlled partition (so the location on disk didn't vary) and rebuilt
> the file system each time (to manage fragmentation).  But, even the dd
> from /dev/zero to /dev/null seems rather wonky to me.
> 
>         I also find it hard to believe, just from personal experience, that
> Xen
> would beat OpenVZ for anything.  I've run Xen and I have OpenVZ in
> production.  I've got a couple dozen OpenVZ VM's running on a single
> platform with virtually no major load average problem (400+ processes at
> any one time) where VMware crushed the processor at less than a dozen
> and Xen couldn't even keep up with that (no HW virtualization).
> 
>         They also show Xen outperforming VirtualBox (I would have loved to see
> a VMware comparison in there as well) but that is totally contrary to my
> experience both with an without HW virtualization (but I noticed they
> were using HW virt for Xen and had it disabled for VirtualBox for at
> least some of the tests...  Hmmm...).
> 
>         I have first hand hands on experience with VMware, VirtualBox, Xen
> (with and without HW vt), OpenVZ, Linux-Vservers, and kvm.  Their
> results are too at odds with my experience.
> 
>         Mike
> --
> Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
>    /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
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>