Re: [libvirt] virsh migrate with libvirt-0.5.1: failed to start listening VM
On Tue, Jul 14, 2009 at 01:13:03PM -0500, Charles Duffy wrote:
Scott Baker wrote:
> You're supposed to have /var/lib/libvirt/images mounted via shared storage
> (nfs/cifs/etc) on both machines.
I've heard of folks having trouble doing live migration over NFS --
something with stronger concurrency guarantees (GFS, a shared iSCSI or FC
mount [possibly with cLVM to partition it up], etc) is likely to be a safer
bet.
(Indeed, looking at the documented preferred environment for VMware's
VMotion is probably a good guideline for anything that's going to be
trusted with real production usage -- a separate bonded pair of NICs on
each host, connected to a dedicated network for communication with the SAN
hosting the backing store).
A method I'm going to be trying out very shortly is using DRBD in
dual-primary mode. DRBD will keep LVM volumes (block devices) for
each VM in sync between two nodes. Upon migration, writes will
cease on node A and when ready, begin on node B. You won't have
concurrent writes, so it will be safe to use DRBD directly without a
clustering FS on top (GFS, OCFS2, etc...).
DRBD has scripts for Xen that take care of the details for you.
Haven't seen the same for KVM/QEMU yet, but I imagine it would be
pretty similar.
--
Garry Dolley
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