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Re: [Qemu-devel] [RFC PATCH] drive-backup 'stream' mode
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [RFC PATCH] drive-backup 'stream' mode |
Date: |
Fri, 11 Oct 2013 09:38:41 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 |
On 10/11/2013 09:18 AM, Wolfgang Richter wrote:
> Idea: Introduce a mode for drive-backup that duplicates writes to
> another target, not CoW. It is useful for introspecting (my use
> case), and for keeping a remote block device in sync with writes
> (helps with migration or backup).
>
>
>
> This is based off of v1.6.0 code.
Best to rebase it against latest qemu.git.
> +++ b/qapi-schema.json
> @@ -1311,12 +1311,14 @@
> #
> # @full: copies data from all images to the destination
> #
> -# @none: only copy data written from now on
> +# @none: only copy on write data written from now on
> +#
> +# @stream: copy every new write to target
Add the designation '(since 1.7)' to make it obvious when this mode was
introduced.
> #
> # Since: 1.3
> ##
> { 'enum': 'MirrorSyncMode',
> - 'data': ['top', 'full', 'none'] }
> + 'data': ['top', 'full', 'none', 'stream'] }
MirrorSyncMode is used by multiple commands; your summary mentions how
it would affect 'drive-backup', but what happens to 'drive-mirror'? For
that matter, why isn't 'drive-mirror' with mode 'none' doing what you
already want?
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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