[Qemu-devel] Re: [PATCH 0/3 v5] Live migration without shared storage

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

Avi Kivity wrote:
> On 11/03/2009 11:40 AM, Liran Schour wrote:
>> - Liran
>>
>> Avi Kivity<avi@redhat.com>  wrote on 02/11/2009 20:47:34:
>>   
>>> On 11/02/2009 03:40 PM, 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).
>>>>
>>>> Live migration will work as follows:
>>>> (qemu) migrate -d tcp:0:4444 # for ordinary live migration
>>>> (qemu) migrate -d blk tcp:0:4444 # for live migration with
>>>>        
>>> complete storage copy
>>>     
>>>> (qemu) migrate -d blk inc tcp:0:4444 # for live migration with
>>>>        
>>> incremental storage copy, storage is cow based.
>>>     
>>>>        
>>> I'd like to see the syntax generalized.  For one, the guest may have
>>> several disks; an install image cdrom might be available as an nfs image
>>> but the main storage is local.  Secondly, there can be several levels of
>>> cow and we want to control which one we copy.
>>>
>>> I'll leave the exact details to the qpeople, but if we can specify a
>>> copy depth for each device, where 0=copy nothing, n=copy everything,
>>> 1=copy the last level (equivalent to -d blk inc) I think we'll have
>>> covered everything.
>>>      
>> I propose the following syntax:
>> migrate [-d] [-b [<device:copy_level>  ...<device:copy_level>]]
>> tcp:<host>:<port>
>> Where device will be the name of the device: ide0-hd0. And copy_level
>> will
>> be integer or n, 0=flat copy of the device, 1=copy the last level ...
>> n=copy all levels.
>> All HD devices that will not appear in the command will be treated as
>> copy_level=0. All devices != BDRV_TYPE_HD will be ignored.
>>
>>    
> 
> Looks good.
> 

Do I get this correctly: this series is now "only" blocked by the
required rework of its user interface? Is there a schedule for this, a
v6 roll out? Will it be in time for qemu-0.12?

Jan

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