Is it possible to resize/copy persistant disk image?

[mark.johnson]

Ok, here's the deal:
I have a persistant disk image with programs I've installed/upgraded and my music etc on.
I want to move the image to an external hard drive.
The trouble is, the external drive is too small for the image (although not the contents of the image).

So, to my question:
Is it possibly to resize a persistant disk image?

And my second question:
Is it possible to copy the contents of one image to another? I've tried creating an image on the external drive, then mounting both images and copying the contents of the old one to the new one, but it just yells at me saying it can't create folders. Is there anything I can do with permissions to make this possible?

Thanks,
Mark

[mark.johnson]

Anyone? Even if it's not possible I'd like to know so I can get on finding an alternative solution.

Mark

[Cuddles]

mark.johnson,

I dont have a clue, maybe some ideas, but, only theoretical...

Can you create "another" image, this one being smaller, and then "copy" the contents of one, into the other ? ( and will the image still retain its contents properly? )

Does the system "keep" these image settings somewhere, and thus, these settings can be "tweaked" with resizing software ?

I cant imagine this not being something someone else hasnt come up against, and possibly resolved... Have you tried a "Search" for any relevant information? Possibly a google for something related, or within this site?

I've never worked with image files, not of the file system/disk type, so, I dont have any answers, mostly, more questions... But, I tried as best as I can here
Ms. Cuddles

[mark.johnson]

Hi Cuddles,
I've tried to create a smaller image and copy the contents across, but it tells me it's unable to create anything in the new image.

Thanks for your help anyway, I'll try searching again

mark

[mark.johnson]

I've solved the problem. So if you need to downsize a persistent image, here's how it's done:

You will need:
Your larger disk image
Enough space for the smaller disk image

Firstly, boot knoppix without any persistant images/home dir of any sort.
Create the new, smaller disk image (doesn't matter if it's on the wrong device, you can move it later)
As root (or using File Manager - Super User Mode) create mnt/oldimg and mnt/newimg
Ensure that you have read/write access to both of these directories
On the desktop, there should be icons for the devices with your 2 knoppix.img files on. Right click the icons, select Properties, and on the device tab, uncheck "Read Only". When you have done this for both devices, click the icons to mount them.
As root, ensure you have read/write access to both knoppix.img files.
Now, mount the images using

mount -o loop mnt/[device]/knoppix.img mnt/oldimg
mount -o loop mnt/[otherdevice]/knoppix.img mnt/newimg

Open /mnt/newimg and /mnt/oldimg in File Manager - Super User Mode
Copy all the folders from /mnt/oldimg to /mnt/newimg EXCEPT FOR /dev AND /lost+found
When the copy process finishes, change the permissions of the knoppix.img files back, and you're done!

Mark

[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/