Hi Blair, Hum so the problem is: While block-migrating a VM with local ephemeral storage (VM disk is a file under /var/lib/nova/instances/) the RBD volume attached to the instance gets copied also? Am I correct? –––– Sébastien Han Cloud Engineer "Always give 100%. Unless you're giving blood.” Phone: +33 (0)1 49 70 99 72 Mail: sebastien.han@xxxxxxxxxxxx Address : 11 bis, rue Roquépine - 75008 Paris Web : www.enovance.com - Twitter : @enovance On 19 Mar 2014, at 13:57, Blair Bethwaite <blair.bethwaite@xxxxxxxxx> wrote: > Hi Sebastian, > > As you seem to favor this configuration too, and are very knowledgeable in these areas, I wonder if you have found an answer to my question about block-migration with attached volumes? > > Best regards, > ~Blair > > > On 18 March 2014 09:08, Blair Bethwaite <blair.bethwaite@xxxxxxxxx> wrote: > Message: 20 > Date: Mon, 17 Mar 2014 16:05:17 +0100 > From: Sebastien Han <sebastien.han@xxxxxxxxxxxx> > To: "Don Talton (dotalton)" <dotalton@xxxxxxxxx> > Cc: "ceph-users@xxxxxxxxxxxxxx" <ceph-users@xxxxxxxxxxxxxx> > Subject: Re: [ceph-users] qemu non-shared storage migration of nova > instances? > Message-ID: <86ED699A-DE8B-4864-860F-E324A6F11CC5@xxxxxxxxxxxx> > Content-Type: text/plain; charset="windows-1252" > > Hi, > > I use the following live migration flags: VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST > It deletes the libvirt.xml and re-creates it on the other side. > > We use this setup (local direct-attached ephemeral storage and Ceph for persistent volumes) in a production OpenStack cloud. The biggest problem (which I think is still present with newer Qemu&Libvirt, though we are on 1.0 and 1.1.1 respectively at the moment) with this is that live-block-migrations copy all block device contents from source to destination... i.e., even volumes get transferred in a ridiculous sequence of "source hypervisor reads blocks from storage cluster -> source hypervisor streams blocks to destination hypervisor -> destination hypervisor writes blocks back to the storage cluster". > > Is that something others have run into and found workarounds for? > > -- > Cheers, > ~Blairo > > > > -- > Cheers, > ~Blairo
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