Re: [Xen-devel] [RFC][PATCH] Increase hotplug timeout

["Daniel P. Berrange" <berrange@xxxxxxxxxx>]

On Thu, Apr 16, 2009 at 11:48:58AM +0100, Ian Jackson wrote:
> Jiri Denemark writes ("[Xen-devel] [RFC][PATCH] Increase hotplug timeout"):
> > When a process in dom0 is writing huge amount of data to a disk in
> > parallel to creating new domain, it may take quite a lot of time
> > until all hotplug scripts finish. For example, on my system it takes
> > almost 5 minutes to start all hotplug scripts.
> 
> That's a very long time.  All of that for just one domain ?
> 
> > So it seems 100 seconds is not enough for such scenarios as xend
> > would give up waiting for hotplug scripts too early. What do you
> > think about the attached patch, which increases the timeout to 10
> > minutes? Of course, the dark side of this change is that it would
> > take ages to recognize hotplug scripts are not really working.
> 
> I think very few people have configurations like yours.

It is a problem that gets more common as you add more devices. eg if
you have lots of disks or nics then it becomes much more likely to
occur. Add in a 2nd guest which is doing alot of I/O at the same time
you are trying to start this guest and it gets worse again, because
xenstored I/O performance starts to hurt. Having xenstored on tmpfs 
should make it happen less. Having a fully in memory xenstored without
any need for tmpfs at all, would be even better.


Daniel
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