[Qemu-devel] Re: [PATCH 0/3 v3] Live migration without shared storage

[Liran Schour]

Jan Kiszka <address@hidden> wrote on 17/09/2009 17:03:04:

> address@hidden wrote:
> > This series adds support for live migration without shared storage,
means
> > copy the storage while migrating. It was tested with KVM. Supports 2
ways
> > to replicate the storage during migration:
> >  1. Complete copy of storage to destination
> >  2. Assuming the storage is cow based, copy only the allocated
> >     data, time of the migration will be linear with the amount of
allocated
> >     data (user responsibility to verify that the same backend file
reside
> >     on src and destination).
>
> For my understanding: Does it require the use of qcow[2] or does it also
> work with raw images?

If you call migrate -b it will do a full copy of the disk,
if you call migrate -i it will do incremental copy means that if you have
qcow disk it will copy only the allocated data. The base image should be
identical
in both source and destination.

> >
> > Live migration will work as follows:
> > (qemu) migrate -d tcp:0:4444 # for ordinary live migration
> > (qemu) migrate -d -b tcp:0:4444 # for live migration with complete
> storage copy
> > (qemu) migrate -d -i tcp:0:4444 # for live migration with
> incremental storage copy, storage is cow based.
> >
> > The patches are against qemu.git tree
>
> ...but without signed-off. Are they RFC for now or do you propose them
> for merge?

I think that RFC is good for now.

> Jan
>
> PS: I think there are some style issues remaining like tabs or long
lines.

Thanks I will fix that.

- Liran