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Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] Add reduce image for qcow2
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From: |
Richard W.M. Jones |
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Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] Add reduce image for qcow2 |
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Date: |
Wed, 31 May 2017 17:10:26 +0100 |
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User-agent: |
Mutt/1.5.20 (2009-12-10) |
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
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