Fedora 11 on XEN Host

[sungsoo khim]

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?

[Pasi Kärkkäinen]

On Thu, Dec 17, 2009 at 01:49:48PM -0800, sungsoo khim 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?
>   
- Are the Fedora guests PV or HVM? 
- Do CentOS guests work OK? 
- Does dom0 have load, big cpu-usage or io-wait? 
- What does "xm top" say?

-- Pasi