Is it possible to resize/copy persistant disk image?

[rwcitek]

Is it possibly to resize a persistant disk image?

Yes. You can resize (shrink and grow) a persistent disk image (PDI) using a combination of dd, e2fsck, and resize2fs. For example, say you have a 200 MB knoppix.img file with only 100 MB of content on /dev/hda1. You want to shrink the image to 110 MB so that the image still has a little bit of room. Here's how:

• boot: knoppix -b
  mkdir /mnt/hda1
  mount /dev/hda1 /mnt/hda1
  cd /mnt/hda1
  e2fsck -pf knoppix.img
  resize2fs knoppix.img 102M
  dd of=knoppix.img bs=1 count=0 seek=110M
  e2fsck -pf knoppix.50.img
  resize2fs -f knoppix.img
  e2fsck -pf knoppix.50.img
  cd
  umount /mnt/hda1
  rmdir /mnt/hda1
  exit

To expand by 10 MB:

• boot: knoppix -b
  mkdir /mnt/hda1
  mount /dev/hda1 /mnt/hda1
  cd /mnt/hda1
  dd if=/dev/zero bs=1M count=10 >> knoppix.img
  e2fsck -pf knoppix.img
  resize2fs -f knoppix.img
  cd
  umount /mnt/hda1
  rmdir /mnt/hda1
  exit

The -b option to Knoppix boots linux into "emergency mode" which is before any PDI is mounted. This allows you to boot linux, make changes to the image (or anything else), and then continue booting with the new image.

For more details, see:
http://lists.firepipe.net/pipermail/...ay/002604.html
http://lists.firepipe.net/pipermail/...ay/002633.html

Note: Be very careful with the dd comand. One slip up and your data is gone. You may want to make a backup of any images just in case.

Is it possible to copy the contents of one image to another?

Yes. Mount both images via the loopback device and then copy. For example, say you want to copy file "foo" from knoppix.01.img to knoppix.02.img:

• boot: knoppix -b
  mkdir /mnt/hda1 /mnt/img.1 /mnt/img.2
  mount /dev/hda1 /mnt/hda1
  cd /mnt/hda1
  mount -o loop knoppix.01.img /mnt/img.1
  mount -o loop knoppix.02.img /mnt/img.2
  cp -a /mnt/img.1/home/knoppix/foo /mnt/img.2/home/knoppix
  cd
  umount /mnt/hda1 /mnt/img.1 /mnt/img.2
  rmdir /mnt/hda1 /mnt/img.1 /mnt/img.2
  exit

Good luck and let us know how things go.

Regards,
- Robert
http://www.cwelug.org/