From: Markus Armbruster <armbru@redhat.com>
To: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: kwolf@redhat.com, vsementsov@virtuozzo.com, den@virtuozzo.com,
qemu-block@nongnu.org, qemu-devel@nongnu.org, mreitz@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 1/3] qcow2: introduce compression type feature
Date: Tue, 09 Jul 2019 08:15:10 +0200 [thread overview]
Message-ID: <87ef2zag41.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <20190704130949.14017-2-dplotnikov@virtuozzo.com> (Denis Plotnikov's message of "Thu, 4 Jul 2019 16:09:47 +0300")
Denis Plotnikov <dplotnikov@virtuozzo.com> writes:
> The patch adds some preparation parts for incompatible compression type
> feature to QCOW2 header that indicates that *all* compressed clusters
> must be (de)compressed using a certain compression type.
>
> It is implied that the compression type is set on the image creation and
> can be changed only later by image conversion, thus compression type
> defines the only compression algorithm used for the image.
>
> The goal of the feature is to add support of other compression algorithms
> to qcow2. For example, ZSTD which is more effective on compression than ZLIB.
> It works roughly 2x faster than ZLIB providing a comparable compression ratio
> and therefore provide a performance advantage in backup scenarios.
>
> The default compression is ZLIB. Images created with ZLIB compression type
> are backward compatible with older qemu versions.
>
> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
QAPI schema
Acked-by: Markus Armbruster <armbru@redhat.com>
next prev parent reply other threads:[~2019-07-09 6:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-04 13:09 [Qemu-devel] [PATCH v2 0/3] add zstd cluster compression Denis Plotnikov
2019-07-04 13:09 ` [Qemu-devel] [PATCH v2 1/3] qcow2: introduce compression type feature Denis Plotnikov
2019-07-09 6:15 ` Markus Armbruster [this message]
2019-08-07 23:12 ` Max Reitz
2019-08-08 0:09 ` Eric Blake
2019-08-08 12:48 ` Max Reitz
2019-08-08 0:18 ` Eric Blake
2019-08-08 12:50 ` Max Reitz
2019-08-08 14:07 ` Kevin Wolf
2019-07-04 13:09 ` [Qemu-devel] [PATCH v2 2/3] qcow2: rework the cluster compression routine Denis Plotnikov
2019-08-08 13:30 ` Max Reitz
2019-08-08 14:39 ` Max Reitz
2019-07-04 13:09 ` [Qemu-devel] [PATCH v2 3/3] qcow2: add zstd cluster compression Denis Plotnikov
2019-07-09 6:18 ` Markus Armbruster
2019-07-30 14:42 ` Denis Plotnikov
2019-08-08 0:24 ` Eric Blake
2019-08-08 14:44 ` Max Reitz
2019-07-30 14:45 ` [Qemu-devel] [PATCH v2 0/3] " Denis Plotnikov
2019-08-07 7:12 ` Denis Plotnikov
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