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

[Jan Kiszka <jan.kiszka@siemens.com>]

Liran Schour wrote:
> Jan Kiszka <jan.kiszka@siemens.com> wrote on 17/09/2009 17:03:04:
> 
>> lirans@il.ibm.com 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.

Ah, ok. So this doesn't affect the feasibility, "just" the effort needed
for the replication.

> 
>>> 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.

[RFC][PATCH ...] :)

Jan

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