Re: [Xen-users] Most stable Xen, and LTS distros

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Tue, Feb 23, 2010 at 01:22:43PM +0100, Fischer Udo Attila wrote:
> Hi all,
>
> As here some people with long year daily practice I have some questions:
>
> Which is the most stable xen hypervisor, with good I/O performance?
>

Not only Xen hypervisor, but also dom0 kernel will highly impact the 
performance.

> - Setup will be dom0 will have drbd on lvm and used as disk space for  
> host, failover to other drbd node.
>

I don't really have experience about drbd with Xen, so can't comment about it.

> - Heartbeat will be used, drbd primary activation will be done by Xen  
> script. (It was the only real stable solution, where drbd could gone  
> secondary on other side).
> - No pci, usb passthrough needed, only good I/O performance between   
> DomU-Hypervisor-Dom0 due it doing the network mirroring.
> - It should be stable, an extra 2-5% overhead is not an issue.
> - I do not need jumbo frame any, due this bridge-start problem, I moved  
> this part to Infiniband, due the used hw prices are very low:)
> - Live migration will not be used due not exactly the same hw and it  
> failed 5%.  Load balance not needed, the systems must be restarted when  
> a kernel update happens, so it will also cause an outage, and by hw  
> failure an outage of  5+1 minutes is acceptable... (ok the Dom0 kernel  
> update cause a +2 minutes outage, but still will be in the 5 minutes 
> window)
>

http://wiki.xensource.com/xenwiki/XenDom0Kernels

I'd suggest you to run Xen 3.4.2 (or latest xen-3.4-testing.hg 3.4.3-rc version)
and linux-2.6.18-xen.hg as a starting point. 

When you have verified that setup works well move possibly to opensuse
forward-ported xenlinux patches (2.6.31.x).

>
> I am using SuSE/OpenSuse for over ten years, but the buggy latest  
> release and the shortening of the update maintenance period has forced  
> me to look around for other distros for Dom0. 
>

What kind of bugs have you experienced?

> I realized, thet  
> Redhat/CentOS has a kernel with a bug, which looks will not be corrected  
> due backport problems (I looked at the kernel code and the official  
> patch is for a later kernel version, and the base code has changed a  
> lot). 
>

What bug is this? bugzilla url?

> It makes unloading the iptables modules impossible, when the  
> Infiniband network is running... (the modprobe process stucks at 100%,  
> not killable).

Oh.. interesting.

> Is there any Xen Dom0 kernel maintained, witch can be used to the  
> Redhat/Centos 5.4?
>

rhel5/centos5 default kernel-xen is usually ok.. if you can't use that,
then I don't really know.. perhaps the SLES11 2.6.27 kernel-xen ?

> I do not want to totally wanted to go to an Debian based as the Ubuntu  
> LTS, as I read it does not support the Xen out of the box as OpenSuse or  
> Redhat does. Has anybody experience with that? Has the Debian version  
> any open bugs Xen related?
>

Yes, many. Especially the Debian Lenny linux-image-2.6.26-2-xen has known bugs 
in it.

> Maybe I will use opensuse 11.1 and planning updates within a year when  
> RHEL 6 comes out....
>

RHEL6 won't have Xen dom0 support included (afaik). It will run as Xen domU 
(guest) though.

> Have somebody experience with Kvm vs Xen performance, when the Dom0 or  
> the Host OS doing raid or even drbd? Because the most I/O will go  
> through the DomU->Hypervisor->Dom0->(Hypervisor->)Infiniband/Network  
> path maybe there will be more overhead by drbd disk performance in case  
> of bare metal hypervisor.
>

I can't unfortunately help with this question.

-- Pasi


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users