From: "Richard W.M. Jones" <rjones@redhat.com>
To: Pavel Butsykin <pbutsykin@virtuozzo.com>
Cc: Eric Blake <eblake@redhat.com>,
qemu-block@nongnu.org, qemu-devel@nongnu.org, kwolf@redhat.com,
armbru@redhat.com, mreitz@redhat.com
Subject: Re: [Qemu-devel] [PATCH 0/2] Add reduce image for qcow2
Date: Wed, 31 May 2017 17:10:26 +0100 [thread overview]
Message-ID: <20170531161026.GG27432@redhat.com> (raw)
In-Reply-To: <a3ee5a6d-b16f-c4fd-b66e-da80d06f30a9@virtuozzo.com>
On Wed, May 31, 2017 at 06:54:33PM +0300, Pavel Butsykin wrote:
> It is assumed that the user has already made a preparatory with the
> image:
> 1. freeing space at the end of the image
> 2. reducing the last partition on the disk
> 3. rebuilding fs
> Only after these steps, the user can reduce the image by qemu-img.
It's tricky with GPT, as GPT puts a second copy of the header in the
last few sectors of the disk. I always advise people to use trim (or
virt-sparsify) instead of trying to adjust virtual disk size.
Nevertheless I don't think we should prevent shrinking qcow2 virtual
size. It's likely useful to someone.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v
next prev parent reply other threads:[~2017-05-31 16:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-31 14:43 [Qemu-devel] [PATCH 0/2] Add reduce image for qcow2 Pavel Butsykin
2017-05-31 14:43 ` [Qemu-devel] [PATCH 1/2] qcow2: add reduce image support Pavel Butsykin
2017-06-01 14:41 ` Kevin Wolf
2017-06-02 9:53 ` Pavel Butsykin
2017-06-02 13:33 ` Kevin Wolf
2017-05-31 14:43 ` [Qemu-devel] [PATCH 2/2] qemu-iotests: add reducing image test in 025 Pavel Butsykin
2017-05-31 14:54 ` Pavel Butsykin
2017-06-01 9:14 ` Kevin Wolf
2017-05-31 15:03 ` [Qemu-devel] [PATCH 0/2] Add reduce image for qcow2 Eric Blake
2017-05-31 15:54 ` Pavel Butsykin
2017-05-31 16:03 ` Max Reitz
2017-05-31 17:01 ` Pavel Butsykin
2017-05-31 16:10 ` Richard W.M. Jones [this message]
2017-05-31 17:39 ` Pavel Butsykin
2017-06-01 9:12 ` Kevin Wolf
2017-06-01 11:11 ` Denis V. Lunev
2017-06-01 11:31 ` Kevin Wolf
2017-06-07 13:37 ` Max Reitz
2017-06-07 15:51 ` Kevin Wolf
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