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This will work for these filesystems:


Note sys-apps/convertfs has been removed from portage (see below referenced bug).

Best way is the simple way - boot from a live cd, mount the partition you wish to convert (read-only), then copy to somewhere useful (an external USB drive for example) using something like 'cp -dPRp'; unmount the copied partition, reformat it with the new filesystem, mount it back up and copy everything back.

From here on, the method requires sys-apps/convertfs which is no longer provided, or considered safe. Also the claims about O(N) don't appear to hold up.

This can cause corrupt filesystems. Always backup your data.

There are some reports of severe data corruption - be warned

Please read Bug 107635 before continuing.

If the partition you are converting is big and full of data be prepared for a really long wait, the conversion cannot be interrupted (it will result in a damaged/corrupted filesystem depending on the stage). The complexity of the algorithm used is O(N) where N is the size of the filesystem.

Getting Started


emerge convertfs

Next get yourself a gentoo ISO

Reboot with the cd in the drive and mount your root partition

mount /dev/hdxx /mnt/gentoo

Now copy the following files from /mnt/gentoo/sbin/ to /tmp/:

  • convertfs
  • convertfs_dumb
  • devclone
  • devremap
  • prepindex

Set your path to include /tmp via export PATH=$PATH:/tmp

Rename convertfs to convfs, because convertfs wants to create a directory named convertfs in /tmp.

Now unmount the drive

umount /mnt/gentoo

Converting the Partition

Now convert the partition

cd /tmp/

convfs /dev/hdxx current_fs new_fs

After the conversion is done it's probably a good idea to run fsck

  • reiserfsck program is used to check and repair a linux reiserfs filesystem.
  • xfs_repair program is used to repair a linux xfs filesystem.
  • fsck.jfs program is used to check and repair a linux jfs filesystem.
  • e2fsck program is used to check and repair a linux ext2 or ext3 filesystem.

So something like:

fsck.jfs /dev/hdxx

Checking The New System

Next, mount the filesystem,

mount /dev/hdxx /mnt/gentoo

and then proceed to edit /mnt/gentoo/etc/fstab to use the correct filesystem, reboot, and you're done..

See Also

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Last modified: Mon, 07 May 2007 06:43:00 +0000 Hits: 33,112