changing filesystem format from xfs to ext4 without losing data
fstransform converts between ext2, ext3, ext4, jfs, minix, xfs, reiserfs.
I see it in Debian repositories, so it probably is also available in other Debian-based distributions.
i am unaware of any way to non-destructively convert a file system. this does not mean it is impossible, but i would put it at very low odds.
you can, for example, convert from ext2
to ext3
without wiping the disk, and from ext3
to ext4
.
but to go from something like jfs
to ext4
seems highly improbable, without first copying your /home
files to another partition or external hard disk.
even then, you would want to create a new user on your system, with a home directory somewhere like /tmp/tempuser
or copy your configurations for your user, usually the 'dot' files (files beginning with .
) in your home directory to a new location off /home
and updating /etc/passwd
to use the new home directory, so you can log in as a normal user while you're performing this update.
then, back up your files, unmount /home
and format it using /sbin/mkfs.ext4
or whatever tool you plan to use. mount the fresh partition at /home
and copy your files back.
also, i would recommend something 'intelligent' like rsync
to copy your files, to assure you preserve your permissions and all that jazz.
You can try http://tzukanov.narod.ru/convertfs/ When I used it a few years ago it worked in one case and trashed the file system in another case.