| |
|
 |
|
 |
|
|
|
| |
|
|
xen-users
Re: [Xen-users] Xen 3.4.3 - bad IO performance on drbd devices
On Tue, Jul 20, 2010 at 10:46:34AM +0200, Felix Botner wrote:
> Hi everyone,
>
> i have two servers installed with a debian/lenny based os (64bit), a
> debian/sid based kernel 2.6.32-xen-amd64 and xen 3.4.3-4. Each server has two
> drbd devices (protocol c, formatted with ext4) and is primary for one of
> them. Every drbd pair has a dedicated network interface (a bond mode 0
> interface with two 1000 Mbps cards).
>
<snip>
>
> The io performance on the connected drbd devices is significantly worse if i
> start the kernel with the xen hypervisor (with "kernel /boot/xen-3.4.3.gz").
> Without the hypervisor (but the same kernel) the systems are about 50%
> faster.
>
Are you measuring from dom0 or from a guest?
>
<snip>
>
> Why is there such a difference?
> Can i optimize my xend (i already added dom0_mem=2048M dom0_max_vcpus=2
> dom0_vcpus_pin as boot parameter with no effect)?
> Are there any known issues using XEN and bonding/drbd?
>
> Feel free to ask for more information about the system or the setup.
>
How much memory does your server have?
ie. how much ram do you have when you boot it baremetal without Xen.
Remember all the free memory of the host/dom0 will be used by linux pagecache..
So if you limit dom0 to 2GB, it'll have less cache than the baremetal case.
-- Pasi
> Many thanks
>
> --
> Felix Botner
>
> Open Source Software Engineer
>
> Univention GmbH
> Linux for your business
> Mary-Somerville-Str.1
> 28359 Bremen
> Tel. : +49 421 22232-0
> Fax : +49 421 22232-99
>
> botner@xxxxxxxxxxxxx>
> http://www.univention.de
>
> Geschäftsführer: Peter H. Ganten
> HRB 20755 Amtsgericht Bremen
> Steuer-Nr.: 71-597-02876
>
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users
|
|
|
| |
|
Home