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Re: [Qemu-devel] Image streaming and live block copy
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] Image streaming and live block copy |
Date: |
Thu, 16 Jun 2011 16:30:18 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Jun 16, 2011 at 11:52:43AM -0300, Marcelo Tosatti wrote:
This approach does not use the backing file feature?
> blkstream block driver:
>
> - Maintain in memory whether given block is allocated in local image,
> if not, read from remote, write to local. Set block as local.
> Local and remote simply two block drivers from image streaming driver
> POV.
> - Once all blocks are local, notify mgmt so it can switch to local
> copy.
> - Writes are mirrored to source and destination, minding guest writes
> over copy writes.
We open the remote file read-only for image streaming and do not want to
mirror writes.
If QEMU crashes or there is a power failure we need to restart the
streaming process carefully - local blocks must not be overwritten.
Perhaps this is the tricky part.
> Over this scheme, you'd have:
>
> 1) Block copy.
> Reopen image to be copied with
> blkstream:/path/to/current-image:/path/to/destination-image,
> background read sectors 0...N.
>
> 2) Image stream:
> blkstream:remote-image:/path/to/local-image,
> background read sectors 0...N.
Stefan
- [Qemu-devel] [PATCH 02/13] block: add -drive copy-on-read=on|off, (continued)
- [Qemu-devel] [PATCH 02/13] block: add -drive copy-on-read=on|off, Stefan Hajnoczi, 2011/06/14
- Re: [Qemu-devel] [PATCH 00/13] QED image streaming, Philipp Hahn, 2011/06/15
- [Qemu-devel] Image streaming and live block copy (was: [PATCH 00/13] QED image streaming), Kevin Wolf, 2011/06/16
- Re: [Qemu-devel] Image streaming and live block copy, Anthony Liguori, 2011/06/16
- Re: [Qemu-devel] Image streaming and live block copy, Avi Kivity, 2011/06/16
- Re: [Qemu-devel] Image streaming and live block copy, Kevin Wolf, 2011/06/16
- Re: [Qemu-devel] Image streaming and live block copy, Avi Kivity, 2011/06/16
- Re: [Qemu-devel] Image streaming and live block copy, Marcelo Tosatti, 2011/06/16
- Re: [Qemu-devel] Image streaming and live block copy,
Stefan Hajnoczi <=
- Re: [Qemu-devel] Image streaming and live block copy, Marcelo Tosatti, 2011/06/17
- Re: [Qemu-devel] Image streaming and live block copy, Marcelo Tosatti, 2011/06/17
- Re: [Qemu-devel] Image streaming and live block copy, Stefan Hajnoczi, 2011/06/18
- Re: [Qemu-devel] Image streaming and live block copy, Stefan Hajnoczi, 2011/06/18
- Re: [Qemu-devel] Image streaming and live block copy, Dor Laor, 2011/06/19
- Re: [Qemu-devel] Image streaming and live block copy, Stefan Hajnoczi, 2011/06/24
- Re: [Qemu-devel] Image streaming and live block copy, Dor Laor, 2011/06/26
- Re: [Qemu-devel] Image streaming and live block copy, Kevin Wolf, 2011/06/27
- Re: [Qemu-devel] Image streaming and live block copy, Dor Laor, 2011/06/27
- Re: [Qemu-devel] Image streaming and live block copy, Kevin Wolf, 2011/06/17