Re: [Xen-users] High availability and live migration with just LVMand hardware fencing

[John Madden <jmadden@xxxxxxxxxxx>]

> I see ... Well, there are two good reasons I cannot have cLVM: need snapshots 
> and it's simply not available for SELS10, so I'm going to keep on asking if 
> permitted. 
clvm doesn't do snapshots, so you can't do snapshots from dom0. 
Snapshots aren't of much use in dom0, though (assuming you're handing 
LV's to domU's, which have their own caches), so why does that matter? 
Do your snapshots from within your domU's.  cLVM may not be available on 
SLES10 out of the box, but that doesn't mean you can't add it.
> - What if I would use a seperate volume group for every LV (and for every Xen 
> guest)? Would that help? I suppose not really, since the Xen guest should be 
> migratable, meaning that all nodes would need to have a consistent view no all 
> VG's and LV's. 
Metadata changes cause writes to disks.  Not safe.  I've done this 
before with active/passive clusters where you could somewhat assume some 
safety (i.e., lvm isn't even running on the passive node) but I'd never 
do it on
> - would snapshotting change the LVM meta data?
Yes, a snapshot is a LV.




--
John Madden
Sr UNIX Systems Engineer
Ivy Tech Community College of Indiana
jmadden@xxxxxxxxxxx

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