[CentOS] resize an image file

Brian Mathis brian.mathis at gmail.com
Wed Nov 21 18:34:33 UTC 2007

On Nov 21, 2007 1:26 PM, Jerry Geis <geisj at pagestation.com> wrote:
> I have a 100G disk on an old redhat 7.3 system.
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/hda1             9.6G  2.4G  6.7G  27% /
> /dev/hda3              99G  6.1G   88G   7% /home
> hda2 is 2G swap
> I am trying to back that complete image up on my centos 5 system.
> I can do the dd if=/dev/hda bs=1M | ssh root at machine 'cat > disk.img'
> which gets me the whole 100G.
> As you can see most of the disk is unused.
> Is there a way to trim the resulting image to only be 10G instead of 100G?
> Thanks,
> Jerry

Try gzipping it, or bzip2:

dd if=/dev/hda bs=1M | gzip | ssh root at machine 'cat > disk.img.gz'

Make sure to put the gzip before the ssh, so you'll compress before
you send over the network.

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