Easiest way to merge partitions under debian (unix)?

Question

I have two unix partitions under debian which I would like to merge (disk space problems :/). What would be the easiest way to do it? I think it would be best to tar or copy files from one partition to the other, delete one and resize the other. I will use parted to resize but how should I copy the files? There are links, permissions and devices which need to be moved without change.

Answer 1

You could run the following (as root) to copy the files. It works for symlinks, devices and ordinary files.

cd /partition2
tar cf - . | ( cd /partition1 && tar xf - )

Another way is to use cpio, but I never remember the correct syntax.

Answer 2

You can also use SquashFS to create a mirror of the partition and copy that over. After resizing your 2nd partition, mount the SquashFS image and copy over the necessary files. Keep in mind that your kernel will need SquashFS support to mount the image.

• SquashFS

Answer 3

Since this is Debian with GNU fileutils, cp --archive should work fine.

cp --archive --sparse=always --verbose --one-file-system --target-directory=/TARGET /ORIGIN

If for some reason you’d want to go via GNU tar, you’d need to do something like this:

cd /origin
find . -xdev -depth -not -path ./lost+found -print0 \
    | tar --create --atime-preserve=system --null --files-from=- \
          --format=posix --no-recursion --sparse \
    | { cd /target; tar --extract --overwrite --preserve-permissions --sparse; }

(I’ve done this so many times that I’ve got a file with all these command lines for quick reference.)

Warning: Using GNU "tar" will not copy POSIX ACLs; you'll need to use either the above "cp --archive" method or "bsdtar":

mkdir /target
cd /origin
find . -xdev -depth -not -path ./lost+found -print0 \
    | bsdtar -c -n --null -T - --format pax \
    | { cd /target; bsdtar -x -pS -f -; }