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Re: [Xen-users] Restarting xend - how?

To: Jeff Noxon <jeff@xxxxxxxxxxxxxx>
Subject: Re: [Xen-users] Restarting xend - how?
From: Anthony Liguori <aliguori@xxxxxxxxxx>
Date: Tue, 24 May 2005 16:07:47 -0500
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Jeff Noxon wrote:

I have just discovered that if I remove /var/lib/xend-db/*, xend can be
started again.  I also removed a lockfile.

However, I have only had limited success manipulating domains at that
point.  'xm shutdown' did not work, but destroy did, sort-of.  The domain
lingers around forever with 0 memory allocated to it.  When I start up
my domains again, I get something like this:
What you're seeing is a well-known problem. Xend can corrupt its own saved state and can not handle recovering that state. If it's going to keep doing this, it's going to need some sort of read log to prevent this from happening in the future.

Blowing away that state will allow Xend to restart but alot of that information is needed (since it contains what devices are attached to the domain).

If Xend does not know what devices are attached, it doesn't know what to remove on destroy. The hypervisor won't let a domain completely go away until all of it's resources are removed and this leads to the "zombie" domains that you're seeing.

Xend is being refactored heavily and a new device database is being implemented which should eliminate a lot of these problems. However, this is all a work in progress and there isn't all that much that you can do right now to prevent this.

VM-Tools is a bit more reliable but has less features (and has some issues with the latest unstable). A new version is going to be released shortly.

VM-Tools targets both 2.0 and 3.0 whereas the new Xend code so far is going to require 3.0.

Regards,

Anthony Liguori


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