From: "Daniel P. Berrange" <berrange@redhat.com>
To: Pavel Butsykin <pbutsykin@virtuozzo.com>
Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, kwolf@redhat.com,
mreitz@redhat.com, den@openvz.org, jsnow@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 0/2] Truncate the tail of the image file in qcow2 shrinking
Date: Fri, 22 Sep 2017 10:50:07 +0100 [thread overview]
Message-ID: <20170922095007.GI12725@redhat.com> (raw)
In-Reply-To: <20170922093926.9723-1-pbutsykin@virtuozzo.com>
On Fri, Sep 22, 2017 at 12:39:24PM +0300, Pavel Butsykin wrote:
> Now after shrinking the qcow2 image, at the end of the image file, there might
> be a tail that probably will never be used. Although it will not bring any
> tangible benefit, we can cut the tail if it is. Yes, it will not free up disk
> space, but if the blocks were be allocated sequentially and the image is not
> heavily fragmented then the virtual size of the image file will be commensurate
> with the real size. It also doesn't look like a great plus.. Well, at least we
> can discuss it.
If the block backend has discard support enabled, can't we get the tail
to be discarded rather than merely truncated ?
Regards,
Daniel
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next prev parent reply other threads:[~2017-09-22 9:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-22 9:39 [Qemu-devel] [PATCH v2 0/2] Truncate the tail of the image file in qcow2 shrinking Pavel Butsykin
2017-09-22 9:39 ` [Qemu-devel] [PATCH v2 1/2] qcow2: fix return error code in qcow2_truncate() Pavel Butsykin
2017-09-22 9:39 ` [Qemu-devel] [PATCH v2 2/2] qcow2: truncate the tail of the image file after shrinking the image Pavel Butsykin
2017-09-25 21:44 ` John Snow
2017-09-27 16:00 ` Max Reitz
2017-09-27 16:27 ` Pavel Butsykin
2017-09-27 16:36 ` Max Reitz
2017-09-28 8:57 ` Pavel Butsykin
2017-09-22 9:50 ` Daniel P. Berrange [this message]
2017-09-22 12:33 ` [Qemu-devel] [PATCH v2 0/2] Truncate the tail of the image file in qcow2 shrinking Pavel Butsykin
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