Red Hat Bugzilla – Bug 426926
XEN consistently crash with <=512Mb RAM
Last modified: 2010-11-09 08:34:25 EST
Description of problem:
When trying to install via XEN this applies to both i386 and x86_64 it
consistently crashes with <=512Mb RAM i.e crashes when installing packages.
Install giving your XEN 512Mb of RAM.
Please advise on more information if required. Thanks.
Please provide the logs from virt-manager / virt-install - whichever you used -
they are in /root/.virt-install or /root/.virt-manager.
Also provide /var/log/xen/xend.log.
What architecture is the host OS.
What architecture is the guest OS.
What version are the 'kernel-xen' and 'xen' RPMs.
Is it a fullvirt or paravirt guest ?
If it is a paravirt guest, and you get a kernel-panic please enable guest
logging in /etc/sysconfig/xend, reboot and do the install again - you should
then get a log of the guest kernel in /var/log/xen/console/ which you can attach
to this BZ.
(In reply to comment #1)
> Please provide the logs from virt-manager / virt-install - whichever you used -
> they are in /root/.virt-install or /root/.virt-manager.
I don't have anything in the /root/.virt-manager going back to the 25th December
> Also provide /var/log/xen/xend.log.
Please see attached.
> What architecture is the host OS.
My host is x86_64.
> What architecture is the guest OS.
The guest is either i386 or x86_64
> What version are the 'kernel-xen' and 'xen' RPMs.
[root@localhost /]# rpm -qa xen*
[root@localhost /]# rpm -q kernel-xen
[root@localhost /]# uname -r
> Is it a fullvirt or paravirt guest ?
> If it is a paravirt guest, and you get a kernel-panic please enable guest
> logging in /etc/sysconfig/xend, reboot and do the install again - you should
> then get a log of the guest kernel in /var/log/xen/console/ which you can
> attach to this BZ.
Will set parameter and attach shortly.
Created attachment 290491 [details]
NB - do not run i386 guests on an x86_64 host. This is known to crash and is
not supported in RHEL5.1. If you can reproduce crashes running x86_64 guest on
x86_64 host, that is useful and we can continue to debug in this BZ, but we
can't debug i386 guests on x86_64 hosts.
Opps, just to clarify - my comment about i386 on x86-64 not being supported was
only wrt to paravirt guest. Fullvirt can run i386 on x86_64 without issue.
I've been working with Gavin and can consistently reproduce a crash at the same
place as he can. Difference is that my xen host is i386 with a i386 guest.
I'll need to schedule downtime to restart the xen host to enable client logging
then I'll attach same logs.
Created attachment 290494 [details]
Guest log x86_64
Attached from /var/log/xen/console
This is from trying a guest os install x86_64
Created attachment 290495 [details]
Created attachment 290496 [details]
Guest console log
This is a very old bug, so sorry about that. Is this still an issue? I assume it is, but we can't do much about some of them. For instance, it's well-known that in an x86_64 guest, 512MB is not enough to run anaconda. It runs out of memory, the OOM killer kicks in, and the installation fails.
I've been able to successfully install i386 guests with = 512MB of memory in the past, but going much below that will probably run into problems. Is this consistent with your observations using the latest software?
This is a very old bug, but it still seems interesting to give it a look.
The strange part is that vbd.c calls blk_queue_max_phys_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST) but still we get a request beyond that limit.
If this isn't still reproducing, then I would like to close it out. Gavin, does this still happen?
I believe we can close this bug as I'm now running a new machine with 8GB of RAM so no longer have the need to run with <=512MB
Just out of curiosity I did try a install with the same scenario as per comment#2 and managed to install successfully. Below are the rpm output with a xen running 512 MB successfully.
[root@localhost ~]# rpm -qa xen*
[root@localhost ~]# rpm -q kernel-xen
[root@localhost ~]# uname -r
Clearing out old flags for reporting purposes.