Re: [Qemu-devel] [RFC V5 00/62] QCOW2 deduplication

[Eric Blake]

On 01/16/2013 08:47 AM, Benoît Canet wrote:
> This 3 step patchset implements deduplication in QCOW2.
> 
> First patchset create the core infrastructure for deduplication and enable it
> in QCOW2 image.
> It ends at "qcow2: Enable the deduplication feature."

Psychologically, reviewers tend to shy away from a 62-patch series, as
it implies a major time commitment to go through.  Sending this as three
separate series, with clear instructions in the later ones that they
depend on earlier ones, aids the review process, even if it actually
results in more mail.  This is because each series no longer has quite
as many associated patches and it becomes easier for a reviewer to
tackle one series at a time.

> 
> Second patchset implements some metrics in QMP.
> It ends at "qapi: Return virtual block device deduplication metrics in QMP"
> 
> Third patchset implements asynchronous deduplication.
> It's a work in progress patchset that is included in this post so reviewers
> can have a grasp of where the feature is heading.

Splitting patches into multiple series is especially useful when only
part of the series is ready for inclusion.

> 
> One can compile and install https://github.com/wernerd/Skein3Fish and use the
> --enable-skein-dedup configure option in order to use the faster skein HASH.
> 
> Images must be created with "-o dedup=[skein|sha256]" in order to activate the
> deduplication in the image.
> 
> Deduplication is now fast enough to be usable.
> Nice side effect is that duplicated writes are faster than native QCOW2:
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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