qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: "Richard W.M. Jones" <rjones@redhat.com>
To: Fam Zheng <famz@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Should 'qemu-img commit' sparsify the backing file?
Date: Thu, 5 Nov 2015 08:56:22 +0000	[thread overview]
Message-ID: <20151105085622.GQ29330@redhat.com> (raw)
In-Reply-To: <20151105071449.GH24893@ad.usersys.redhat.com>

On Thu, Nov 05, 2015 at 03:14:49PM +0800, Fam Zheng wrote:
> I don't think this the purpose of "qemu-img commit". Committing
> "new" data in overlay.qcow2 has little to do with discarding backing
> image's fragments where there are only explict zeroes.

In that case, why didn't this step sparsify the backing file?

> > (3) Sparsify the overlay:
> > 
> > $ virt-sparsify --in-place overlay.qcow2 
> > $ du -sh fedora-22.img overlay.qcow2 
> > 6.1G fedora-22.img
> > 3.2M overlay.qcow2
>     qemu-img convert fedora-22.img fedora-22.img.1
> 
> I don't think we have an in-place sparsifier now.

virt-sparsify ...

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

  reply	other threads:[~2015-11-05  8:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-04 16:37 [Qemu-devel] Should 'qemu-img commit' sparsify the backing file? Richard W.M. Jones
2015-11-05  7:14 ` Fam Zheng
2015-11-05  8:56   ` Richard W.M. Jones [this message]
2015-11-05  9:46     ` Fam Zheng
2015-11-05 12:18       ` Richard W.M. Jones
2015-11-09 16:03       ` Kevin Wolf

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20151105085622.GQ29330@redhat.com \
    --to=rjones@redhat.com \
    --cc=famz@redhat.com \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).