[fedora-virt] Fedora 11 on XEN Host

[Dale Bewley]

----- "sungsoo khim" <skhim at ebrary.com> wrote:
> Excuse if this was already discussed. (few hours of searching didn't 
> really help out)
> 
> We have some server running Cent OS 5.4 as Dom0, and a few more fedora
> 
> 11 running on top of them using XEN.
> 
>  From time to time, one or two of our fedora VM's Load Index will rise
> 
> up to 100+ over 8 hour period. (In a very linear fashion)
> 
> When we see the trend starting (regardless of the Load index number at
> 
> the moment) we are not able to login using SSH or even console (xm 
> console [VMNAME]).
> 
> Only way to deal with it is to reboot the VM, and there is no 
> significant log entry at all. to indicate any system specific errors.
> 
> (As if nothing has happened) However, no log message are present
> during 
> the high load period.
> 
> When it happens however, active running process will reply back - such
> 
> as web proxy process. All socket open requests work as should (SSH, 
> HTTP, etc), but will not go further than opening the socket with a 
> greeting message.
> 
> Has anyone had similar experience, and fund a resolution to?

I see something very similar on F8 Xen dom0. It seems to manifest
during high I/O for me, like during a mysqldump of a large db. The
guest system eventually becomes completely blocked.

This one was a record for me:
 load average: 301.04, 301.00, 298.46

Install sar on the guest, and see if you can correlate load increase
with some activity on the system. Maybe you can spread that activity
out.

My solution was to move problematic guests to newer hardware with
support for KVM. Unfortunately, most of my hardware has no such
support.