[libvirt-users] Progressively worsening unresponsiveness

[Martin Kletzander]

On Mon, Aug 25, 2014 at 02:56:57PM -0600, Michael Warnecke wrote:
>Hello all, I'm new to the list, and hoping someone can point me in the
>right direction.
>
>I've got an Ubuntu 14 dom0 with, what I think, are excellent specs.  12
>cores, hyperthreaded, VT, 64GB RAM, gobs of disk, etc... all to run 8
>virtual machines (at the moment).
>
>My problem is each of the guests - Windows, Ubuntu, FreeBSD, starts out
>working fine.  After several minutes, the guest becomes unresponsive for a
>moment, and comes back.  As time goes on, this happens more, and more
>frequently, and longer and longer until after about a day the guest is
>completely useless, and needs a shutdown, and start.
>
>The dom0 is NEVER unresponsive.
>
>I've tried to track this down through every means I have available, and
>have come up empty handed.  Here is some of what I've done so far, please
>let me know what other information would help to debug this:
>
>1. I've set guest OS processor to be default, and copied from host.
>Neither made any noticable difference.
>2. I've switched all disks and network to be VirtIO.  Big improvement over
>IDE, but the unresponsive problem persists.
>3. Linux guests have the following in dmesg:
>hrtimer: interrupt took 10109276 ns
>[sched_delayed] sched: RT throttling activated
>4. I found nothing suspicious in the dom0's dmesg.
>5. Unresponsiveness does not correlate with disk usage.
>6. Host uses 4 disks in software RAID-5 (yes I know I'm bad, but there are
>reasons) using BTRFS.
>7. Guest disks are all raw.
>
>Please let me know if there is some other useful information, or if you
>have an idea where I should look next.
>

I would suggest looking for a bottleneck on the host and then on
guests as well.  I like using atop for this for example.  virt-top can
show you how much each machine eats up.  Check the memory and
processor usage.  What are the settings (CPU, MEM, disks) for the
machines?

It still might be just a minor issue like for example that everything
starts swapping and you're gone then of course.

Martin

>Thanks!

>_______________________________________________
>libvirt-users mailing list
>libvirt-users at redhat.com
>https://www.redhat.com/mailman/listinfo/libvirt-users
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://listman.redhat.com/archives/libvirt-users/attachments/20140826/3d6f4aa3/attachment.sig>