[dm-devel] Use LVM on /dev/mapper/diskname and iSCSI

[malahal at us.ibm.com]

S. J. van Harmelen [svh at dds.nl] wrote:
> 
> On the XenSource server I use a shared iSCSI storage so multiple servers
> can access the same data so I can do live migrations. When I add the
> storage XenSource creates a PV and then when I create a VM, it creates
> LV's for each virtual harddisk.
> 
> So far so good I guess, as the XenSource machine uses the multipathed
> drive, right?

Should.
 
> Now I would like to take snapshots of the whole PV so I can make
> backups. My thoughts where to make a PV on /dev/mapper/xen that spans
> the whole disk, and then create a single LV on it. 
> 
> If I then take the path to that single LV, say /dev/volumegroup/disk1 as
> target for iSCSI, then the XenSsource server should only see that LV as
> the shared iSCSI repository.
> 
> But then XenSource wil create a PV and a couple of LV's in the existing
> LV (created on the storage server and shared true iSCSI). Could that
> create any problems or can I just do that?

I don't see any problem. You should be able to do that, but then I am
not an expert. Give it a try.