Hello,
On 11/14/11 19:16, iS-Fun Internet Services GmbH, Holger Diehm wrote:
> I experienced and sometimes still experience the same. But I think I found a
> reason...or at least one cause of possibly more.
>
> If a domu uses swap and swaps out too much and theres much io on the backend
> (tap, file or isci in my configs) the concerned xenstrored consumes the ram
> for writing to the backend..which starts lagging ugly.
>
> So, for the buggy domains I first suggest:
> a) check available ram/check for swapping
> b) for testing purposes disable swap
> c) I think its most horrible on tap:aio, and normal loop-diskimages. Try to
> switch the backend if you use one of the mentioned.
Thanks for sharing your input, I did some check for one of our dom0 that
has few DomU.
- no swap on the domU
- almost no memory used for 2/3 dom0 (like 2/16MB), and like 2/4MB for
the last one.
- no pick in network traffic either
Plus we also have 2 dom0 that behave that way that are diskless (full
iscsi), with domU also having their disk directly on the network (doing
iscsi on their own, with just network from dom0, the dom0 doesn't know
anything about their disks).
> Meanwhile I started over with no swap for my domus at all, and if RAM is
> needed (oom killer acts in vm ) I balloon it in, or check for the reason -
> for
> me this is a possible way and is a good workaround.
Well, before finding what causes it would be a good start. A way to fix
it and/or having a work around would be something we could consider
*once* we figure what's generating that problem.
> My Dom0s are not up-to-date, perhaps the behaviour is "fixed"/different in
> newer versions than mine (at least 4.0 showes this from time to time).
>
> But, as I say this, it may be something totally different on your side.
If yours is definitely from swap usage, ours has to be different... :(
Regards,
Adrien Urban
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