Re: [Xen-users] Weird ram/dom-u limit problem

[David Halik <dhalik@xxxxxxxxxxxxxxx>]

On 01/20/2010 05:26 PM, Fajar A. Nugraha wrote:
> On Thu, Jan 21, 2010 at 2:20 AM, David Halik<dhalik@xxxxxxxxxxxxxxx>  wrote:
>    
> > I'm hitting what
> > *appears* to be some kind of wall on either the number of vm's or the amount
> > of ram they're using (personally I think it's ram, but I don't see how).
> >      
> Number of vms can be very high (even over 300).
> Ammount of ram is something you can easily see
>
>    
> > loops = 64
> >      
> are you using file:/ or tap:aio?
>    
file. Is there any advantage to running tap over file? I know that the 
driver is superior, and there is less chance of data loss, but we keep 
our data on NFS, so I never really worried to much about it. file: seems 
more manageable to me, but maybe tap is a better way to go? How is the 
comparison in performance?
>    
> > Now, if I attempt to install an 8th vm with 512MB or ram on either server
> > the install runs for awhile and then suddenly load on the xen server begins
> > to grow and grow and grow. Going from a load average: 0.09, 0.15, 0.10 to
> > load average: 10.58, 7.88, 4.70. The box itself begin to become very slow
> > and bogged down. top shows that it's because of cpu iowait, but I can't find
> > any particular reason for it.
> >      
> try running "iostat -mx 3".
> My guess is you're disk I/O bound.
>
>    
I think you're right, I just came to the same conclusion. I moved the 
install to a file on a second drive where the other vm's aren't mounted 
and it worked *much* better. It seems like I'm going to have to do 
installs on a seperate drive and then move the img over. The disk isn't 
I/O bound when the vm's are doing normal work, so I'm only concerned 
about install time.


--
================================
David Halik
System Administrator
OIT-CSS Rutgers University
dhalik@xxxxxxxxxxxxxxx
================================


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users