Restoring dd Image

[jamoody]

I've backed up a LVM share via dd:

dd if=/dev/mapper/VolGroup-lv_root | bzip2 >VolGroup-lv_root.dd.bz2

Can I restore the image to a different directory, eg:

bunzip2 VolGroup-lv_root.dd.bz2 | dd of=backup/

so I can extract and restore certain files?

Can I restore it into the root directory of the live running system that it was backed up from,eg:

bunzip2 VolGroup-lv_root.dd.bz2 | dd of=/dev/mapper/VolGroup-lv_root

Thanks.

[Rubberman]

1. To pipe input/output to/from bzip2/bunzip2, you need to use the -c option.
2. Since you have copied the entire LVM device, you probably cannot just restore it somewhere else, other than perhaps a raw partition that has adequate space.
3. If you uncompress the image, you may be able to mount it as a loop device and access individual files that way.

[ford]

I made a decently comprehensive intro to dd here. It may help you with your backup stuff.

What rubberman was talking about is a command like this:
#dd if=/dev/sdX bs=64k conv=noerror,sync | gzip -c -9 > sdX.img.gz

Restoring that would be something like:
#gunzip -c sdX.img.gz | dd of=/dev/sdX conv=sync,noerror bs=64K

You can specify any path, file, or storage device instead of sdX. If you specify a file you can then do something like:
# mkdir loopedMount
# mount -o loop sdX.backup loopedMount/
This would allow you to peruse those files as if they were on a physical disc mounted to that directory.