Re: [Xen-users] PDFLUSH deadlock

["Fajar A. Nugraha" <fajar@xxxxxxxxxxxxx>]

Gareth Bult wrote:
> Hi,
>
> I did post this before, but as time passes I'm becoming more confident 
> of my observations.
> When using XEN in the way I'm using it, there is a deadlock condition 
> somewhere in PDFLUSH that can lock your machine up.
> The lockup may be very short / un-noticeable, or it may extent to a 
> number of minutes.
> Conditions
> ========
>
> Lots of DomU's (say 10) all running off file-backed storage.
> Cure
> ====
>
> Type "sync" in the Dom0 - instant release.
>
> Things I've tried
> ===========
>
> Tweaking /proc/sys/vm/dirty_*
I had somewhat similar problem when testing vmware-server, running more 
than one guest. Worse, actually, in that at some point the host simply 
hangs.
The fix was to add these entries to /etc/sysctl.conf :

vm.min_free_kbytes = 10240
vm.dirty_expire_centisecs = 500
vm.dirty_writeback_centisecs=250
vm.dirty_ratio=40
vm.dirty_background_ratio=20

I believe the first entry is the most important.
Now I use LVM-backed Xen mostly, so it's not an issue. Perhaps you 
should try LVM and see if it can provide better performance.
Regards,

Fajar

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