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Re: [Xen-users] LVM Read/Write speed <10% drive's normal speed

To: Stephen.Hamer@xxxxxxxxxx
Subject: Re: [Xen-users] LVM Read/Write speed <10% drive's normal speed
From: "Fajar A. Nugraha" <fajar@xxxxxxxxx>
Date: Thu, 17 Sep 2009 22:16:01 +0700
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On Thu, Sep 17, 2009 at 4:49 AM, Stephen Hamer <Stephen.Hamer@xxxxxxxxxx> wrote:

> My setup is this:
>         Xen 3.3 hypervisor (from the ubuntu repositories)
>         Ubuntu 9.04 server
>         Kernel and module listed here:
> http://www.infohit.net/blog/post/running-xen-on-ubuntu-intrepid-and-jaunty.html
> The dom0 and domUs in my Xen setup are all Ubuntu 9.04, using that kernel.
> (I'm not sure if the kernel has something to do with it, so i included it
> just in case.)

I believe which kernel you use matters a lot in this case :)

> All the domUs are set up to use LVM. The dom0 uses a straight
> ext3 fs on /dev/sda1. The domUs use ext3 fs's within LVMs (using LVM2) set
> up on /dev/sda5.
> I have noticed a massive file I/O problem on all of my domUs. While I can
> peak file operations around 100 MB/s within the dom0, I can't get anything
> more than 3 MB/s read OR write out of a file operation on the domUs.

I suggest you try using official xen.org's 2.6.18 kernel, or other
vendor-supported 2.6.18 kernel-xen (like RHEL5's kernel-xen, or even
Etch's kernel) for both domU and dom0 and see if the problem persists.


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