[Pkg-xen-devel] Bug#666135: Bug#666135: Multiple "Domain-0", slow libvirt

[Ian Campbell]

On Mon, 2012-07-09 at 15:06 +0200, Bogdan Ćulibrk wrote:
> 2013  open("/var/lib/xenstored/tdb.0x17a47b0",
> O_WRONLY|O_CREAT|O_TRUNC, 0640) = 153
> 2013  open("/var/lib/xenstored/tdb.0x17a47b0", O_RDWR) = 156
> 2013  rename("/var/lib/xenstored/tdb.0x17a47b0", "/var/lib/xenstored/tdb") = 0
> 2013  unlink("/var/lib/xenstored/tdb.0x17a47b0") = -1 ENOENT (No such
> file or directory)
> ---snip---
> 
> (last 4 lines repeated 80 times)

I suspect (athough I'm not sure) that the creation/deletion of these
tdb.<ID> are an artefact of the stupid way the C xenstored does
transactions (it basically copies the whole db and "commit" is really an
atomic rename)

Is /var/lib/xenstored/tdb huge? If so then as a workaround it might be
helpful to remove it on boot (before xenstored is started), this is
generally a best practice anyway. It is also not uncommon for folks to
redirect it to a ramdisk (i.e. stick a tmpfs on /var/lib/xenstored).
There is no persistent data stored in xenstored so this is safe to do.

C xenstored is pretty sucky but in 4.0/Squeeze I don't think the ocaml
xenstored (aka oxenstored) is available yet.

Ian.