Hi! I think it's a pretty useful feature, a good compromise. As you said using a shared fs implies a lot of things and can dramatically decrease your performance rather than using the local fs. I tested it and I will use it for my deployment. I'll be happy to discuss more deeply with you about this feature :)
I also feel a little concern about this statement: It don't work so well, it complicates migration code, and we are building > a replacement that works. I have to go further with my tests, maybe we could share some ideas, use case etc... Cheers! On Mon, Aug 6, 2012 at 3:08 PM, Blair Bethwaite <blair.bethwa...@gmail.com> wrote: > Hi all, > > KVM block migration support in OpenStack > (https://blueprints.launchpad.net/nova/+spec/kvm-block-migration) > seems to be somewhat of a secret - there's almost nothing in the > docs/guides (which to the contrary state that live migration is only > possible with shared storage) and only a couple of mentions on list, > yet it's been around since Diablo. Should this be taken to mean it's > considered unstable, or just that no-one interested in documenting it > understands the significance of such a feature to deployment > architects? After all, decent shared storage is an expensive prospect > with a pile of associated design and management overhead! > > I'd be happy to contribute some documentation patches (starting with > the admin guide) that cover this. But first I'd like to get some > confirmation that it's here to stay, which will be significant for our > own large deployment. We've tested with Essex on Ubuntu Precise and > seen a bit of weird file-system behaviour, which we currently suspect > might be a consequence of using ext3 in the guest. But also, there > seems to be some associated lag with interactive services (e.g. active > VNC session) in the guest, not yet sure how this compares to the > non-block live migration case. > > We'd really appreciate anybody actively using this feature to speak up > and comment on their mileage, especially with respect to ops. > > I'm slightly concerned that KVM may drop this going forward > (http://www.spinics.net/lists/kvm/msg72228.html), though that would be > unlikely to affect anybody deploying on Precise. > > -- > Cheers, > ~Blairo > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp
_______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
