Re: [Xen-users] XEN and clustering?

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Sat, Feb 27, 2010 at 07:48:50PM +0100, Zoran Popovi? wrote:
>    I had same situation, though I am not using cluster (I am using multipath
>    and raw devices on shared storage). My workaround is issuing:
> 
>    echo 1 > /proc/sys/vm/drop_caches
> 
>    after finishing copy or after an external change (e.g. by action on the
>    shared storage independently from host) on the raw device. It works like a
>    charm, but I am not sure what would be the right solution with cluster and
>    raw devices - GFS is fine with files, CLVM with LVMs, but I am not using
>    LVM either (and CLVM has a drawback - snapshots are not supported).
>

Hmm.. I wonder what's causing that behaviour.

Xen phy: disk backend should skip all dom0 caches, so you should not
need drop_caches..

Ideas how to track resolve this? 

-- Pasi

 
>    ZP.
> 
>    2010/2/27 Jakov Sosic <[1]jakov.sosic@xxxxxxx>
> 
>      Hi.
> 
>      I'm using Xen on RHEL cluster, and I have strange problems. I gave raw
>      volumes from storage to Xen virtual machines. With windows, I have a
>      problem that nodes don't see the volume as same one.... for example:
> 
>      clusternode1# clusvcadm -d vm:winxp
>      clusternode1# dd if=/dev/mapper/winxp of=/node1winxp
>      clusternode2# dd if=/dev/mapper/winxp of=/node2winxp
>      clusternode3# dd if=/dev/mapper/winxp of=/node3winxp
> 
>      When I download these files and diff them, they all three differ.
> 
>      Also, sometimes very strange things happen. For example I download some
>      file into winxp, shut it down, then start it on another node, and file
>      is missing?!?!?!?!
> 
>      Should I use maybe CLVM and not raw volumes from storage? Why is this
>      happening?
> 
>      --
>      |    Jakov Sosic    |    ICQ: 28410271    |   PGP: 0x965CAE2D   |
>      =================================================================
>      | start fighting cancer -> [2]http://www.worldcommunitygrid.org/   |
> 
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