Xen users - Feb 2006 - Re: Dell Poweredge 2650 - heavy IO hangs domU machine s; xen 2.0.7, xen kernel 2.6.11.12

The issues I''ve had with PE2650 and Linux in general all related to a
lack
of IRQ''s.  I had to disable all non-essential devices in the BIOS (lpt,
usb
and com).  It seems the BIOS on that server still has legacy IRQ issues (<
IRQ15).  In my xenU''s I also renamed /etc/sysconf/hwconf so it
would''nt try
to init any hardware devices directly.

Maybe these options could help...good luck
> This is a pretty serious problem... no bites yet? This doesn''t
sound
familiar to anyone?
> It''s not a bacula problem. Bacula doesn''t do this to us
running on
unvirtualized hardware.
 
> Stephen Bosch wrote:
> Hello:
> 
> At the off-list suggestion of another user, we have tried adding
> ''noirqbalance'' to the xen start line in grub,
we''ve disabled USB in the
> system BIOS, and we''ve added ''nousb'' to the
kernel parameters.
> 
> The problem is still there, exactly as before, even with all those
changes.
> 
> *All* the virtual machines lose network connectivity, not just the ones
> involved in the backup. We have an LDAP server VM running on this
> hardware that is totally idle when this hang happens. We cannot ping or
> ssh into them. We can get a console using ''xm console'',
but after
> entering the userid, the login times out (after 60 seconds) before we
> ever get a password prompt.
> 
> I still suspect an interrupt problem: it would appear that the tty is
> unable to do a disk read to do authentication. At the same time, the
> tape backup process hangs.
> 
> If we kill the bacula storage daemon on dom0, all of the virtual
> machines release and we can log in again. At no point does anything
> reboot -- it just hangs, and it''s not a fatal hang. If the backup
> process stops, whether through a timeout or by forceably stopping the
> storage daemon, the virtual machines are again pingable and we can log
> in both with ssh or ''xm console''.
> 
> We tried monitoring the memory usage during the backup test by running
> ''top'' in separate console windows. Loads were actually
modest and there
> was plenty of memory remaining on all the virtual machines (over 1 GB in
> free RAM in one case).
> 
> To recap: this is a Dell *2650*, not a 2850. It has a Serverworks, not
> an Intel chipset. The RAID controller is a PERC 3 DC (LSI Logic) which
> uses the Megaraid drivers. The controller firmware has been upgraded to
> 3.35/1.07, the most recent available.
> 
> Note also -- dom0 is unaffected. We can still interact with dom0 without
> trouble. This hang affects only the virtual machines.
> 
> Cheers,
> 
> -Stephen-
Max Baro 
Technical Support Representative 
FACTS Services, Inc. 
(305) 284 - 7440 
meb@factsservices.com 

 


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