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
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