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Re: [Qemu-devel] [PATCH v12 00/11] Drop in_use from BlockDriverState and
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v12 00/11] Drop in_use from BlockDriverState and enable point-in-time snapshot exporting over NBD |
Date: |
Tue, 28 Jan 2014 15:31:36 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Jan 27, 2014 at 11:48:06AM +0800, Fam Zheng wrote:
> This series adds for point-in-time snapshot NBD exporting based on
> blockdev-backup (variant of drive-backup with existing device as target).
>
> We get a thin point-in-time snapshot by COW mechanism of drive-backup, and
> export it through built in NBD server. The steps are as below:
>
> 1. (SHELL) qemu-img create -f qcow2 BACKUP.qcow2 <source size here>
>
> (Alternatively we can use -o backing_file=RUNNING-VM.img to omit
> explicitly
> providing the size by ourselves, but it's risky because RUNNING-VM.qcow2
> is
> used r/w by guest. Whether or not setting backing file in the image file
> doesn't matter, as we are going to override the backing hd in the next
> step)
>
> 2. (QMP) blockdev-add backing=source-drive file.driver=file
> file.filename=BACKUP.qcow2 id=target0 if=none driver=qcow2
>
> (where source-drive is the running BlockDriverState name for
> RUNNING-VM.img. This patch implements "backing=" option to override
> backing_hd for added drive)
>
> 3. (QMP) blockdev-backup device=source-drive sync=none target=target0
>
> (this is the QMP command introduced by this series, which use a named
> device as target of drive-backup)
>
> 4. (QMP) nbd-server-add device=target0
>
> When image fleecing done:
>
> 1. (QMP) block-job-cancel device=source-drive
>
> 2. (HMP) drive_del target0
>
> 3. (SHELL) rm BACKUP.qcow2
Seems to work as advertized but do you have qemu-iotests for
blockdev-backup and image fleecing in particular?
Stefan
- [Qemu-devel] [PATCH v12 03/11] block: Replace in_use with operation blocker, (continued)
- [Qemu-devel] [PATCH v12 03/11] block: Replace in_use with operation blocker, Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 04/11] block: Move op_blocker check from block_job_create to its caller, Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 05/11] block: Add bdrv_set_backing_hd(), Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 06/11] block: Add backing_blocker in BlockDriverState, Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 07/11] block: Parse "backing" option to reference existing BDS, Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 08/11] block: Support dropping active in bdrv_drop_intermediate, Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 09/11] stream: Use bdrv_drop_intermediate and drop close_unused_images, Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 10/11] qmp: Add command 'blockdev-backup', Fam Zheng, 2014/01/26
- [Qemu-devel] [PATCH v12 11/11] block: Allow backup on referenced named BlockDriverState, Fam Zheng, 2014/01/26
- Re: [Qemu-devel] [PATCH v12 00/11] Drop in_use from BlockDriverState and enable point-in-time snapshot exporting over NBD,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [PATCH v12 00/11] Drop in_use from BlockDriverState and enable point-in-time snapshot exporting over NBD, Fam Zheng, 2014/01/28
- Re: [Qemu-devel] [PATCH v12 00/11] Drop in_use from BlockDriverState and enable point-in-time snapshot exporting over NBD, Stefan Hajnoczi, 2014/01/28