Re: [Xen-users] Re: XEN and clustering?

[Jakov Sosic <jakov.sosic@xxxxxxx>]

On 02/27/2010 06:35 PM, Klaus Steinberger wrote:
> 
>> 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?
> 
> You mean LUN's from a storage? Do you use the GPLPV drivers inside the 
> Windows HVM ?
> 
> Then you probably run into the same or a similar trouble which is described in
> this bug report:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=466681
> 
> 
> Dropping vm caches helps:
> 
> echo 1 > /proc/sys/vm/drop_caches
> 
> Also using clvm helps, but you will loose the snapshot features of the 
> storage,
> lvm snapshot are not possible in a clustered environment.

Thank you very much...

This forces me to migrate 3TB of data to CLVM volumes, but at least I
know that it a working combination... I dropped CLVM because of it's
limits (cluster has to be up for it to map volumes, can't do snapshots
etc), but at least with CLVM everything works.



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|    Jakov Sosic    |    ICQ: 28410271    |   PGP: 0x965CAE2D   |
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