Xen devel - Jun 2011 - dom0 system functions impaired after creating domU on xen4.1 running 2.6.32-jeremy

I decided to migrate from my old Xen platform (xen4.0 with 2.6.31-pvops 
dom0 and 2.6.32 guests) to my new one (xen4.1 with 2.6.32-jeremy dom0 
and 2.6.39 guests).

Everything was going fine when, without indication of any problems, "xm 
create /etc/xen/domains/xy.sxp -c" didnt produce output anymore and the 
guest didnt start. (no output = no kernel booting, no error message, 
nothing, zip, nada)

So i went to cancel the process, destroy the domain, retry with xm, try 
a different guest, but to no avail. (I tried xl too at that point)

Just to se whats going on i ran "ps auxw"  ... it hung itself after 
listing some processes.
So in addition to not beeing able to create new guests i couldnt even 
list my processes.

I live migrated all the guests to another host and went on to "init 6"
the affected server.
At the stage where is suppose all remaining processes received the 
signal to stop, the terminal i initially ran "xm create" on popped out
2
lines of text i sadly neglected to copy (i guess some generic error 
creating domain, or creation cancelled, sth like that)
Additionally "ps auxw" started working again and after a short while
the
box rebooted as expected.


I had noticed this behavior earlier, like 2 weeks ago, but didnt think 
much of it, since i was working on the system configuration and had to 
reboot the server anyway.




Does anybody have a clue what could lead to this behavior?

The systems are pretty much what i would expect most xen hosts to be, 
some linux (debian 6.0 in my case), a current version of Xen and a 
current jeremy pvops dom0 kernel. (kernel is 2.6.32.40 now and was an 
earlier version when i first encountered the problem)

Should i maybe restrain myself from using xm to create guests or even 
from using it altogether? (xl has no live migration and cant xl new ... 
xl start)


Input would be greatly appreciated.

with best regards

-- 
Andreas Olsowski
Leuphana Universität Lüneburg
Rechen- und Medienzentrum
Scharnhorststraße 1, C7.015
21335 Lüneburg

Tel: ++49 4131 677 1309




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On Wed, Jun 15, 2011 at 01:08:25PM +0200, Andreas Olsowski
wrote:
> I decided to migrate from my old Xen platform (xen4.0 with
> 2.6.31-pvops dom0 and 2.6.32 guests) to my new one (xen4.1 with
> 2.6.32-jeremy dom0 and 2.6.39 guests).
> 
> Everything was going fine when, without indication of any problems,
> "xm create /etc/xen/domains/xy.sxp -c" didnt produce output
anymore
> and the guest didnt start. (no output = no kernel booting, no error
> message, nothing, zip, nada)
And you updated the toolstack?

You can add ''earlyprintk=xenboot debug loglevel=10
initcall_debug'' in
the Linux command line (''extra'') to see where it choked.
> 
> So i went to cancel the process, destroy the domain, retry with xm,
> try a different guest, but to no avail. (I tried xl too at that
> point)
> 
> Just to se whats going on i ran "ps auxw"  ... it hung itself
after
> listing some processes.
Uhh.. that is most bizzare.
> So in addition to not beeing able to create new guests i couldnt
> even list my processes.
> 
> I live migrated all the guests to another host and went on to "init
> 6" the affected server.
> At the stage where is suppose all remaining processes received the
> signal to stop, the terminal i initially ran "xm create" on
popped
> out 2 lines of text i sadly neglected to copy (i guess some generic
> error creating domain, or creation cancelled, sth like that)
> Additionally "ps auxw" started working again and after a short
while
> the box rebooted as expected.
> 
> 
> I had noticed this behavior earlier, like 2 weeks ago, but didnt
> think much of it, since i was working on the system configuration
> and had to reboot the server anyway.
> 
> 
> 
> 
> Does anybody have a clue what could lead to this behavior?
Hm, perhaps your disk is not getting the interrupts the bash
shell is blocking on a read? Were there any error messages reported
by ''dmesg''?
> 
> The systems are pretty much what i would expect most xen hosts to
> be, some linux (debian 6.0 in my case), a current version of Xen and
> a current jeremy pvops dom0 kernel. (kernel is 2.6.32.40 now and was
> an earlier version when i first encountered the problem)
> 
> Should i maybe restrain myself from using xm to create guests or
> even from using it altogether? (xl has no live migration and cant xl
> new ... xl start)
I''ve been using them. Not really sure what is happening in your case.

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On Wed, 15 Jun 2011, Andreas Olsowski wrote:
> Should i maybe restrain myself from using xm to create guests or even 
> from using it altogether? (xl has no live migration and cant xl new ... 
> xl start)
xl has live migration but doesn''t have a concept of "installed
guests".
So you use xl executing "xl create /path/to/file".

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