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Re: [Qemu-devel] drive-mirror sync points
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] drive-mirror sync points |
Date: |
Mon, 13 May 2013 21:05:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 |
Il 13/05/2013 19:50, Wolfgang Richter ha scritto:
> Paolo/anyone who knows -
>
> Are drive-mirror sync points (NBD flush commands) reflecting guest write
> barriers? Are guest write barriers respected by drive-mirror? If so,
> that would make drive-mirror much more palatable for disk introspection
> work (a drop-in usable feature of QEMU!).
Kind of. Sync points reflect points where the destination image is a
copy of the source image at some point in time. Destination image write
barriers hence reflect places where the destination image is consistent
with guest write barriers, but not all guest write barriers become
destination image write barriers.
Paolo