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Is it possible to do so ? I am migrating to EXT4 because of the SSD drive that has TRIM funtion. I have to have ext4 partion.

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migrated from Apr 30 '13 at 12:23

This question came from our site for professional and enthusiast programmers.

ext3 or iso? It is mutually exclusive... – glglgl Apr 30 '13 at 12:25

The best answer is probably from the ext4 Wiki itself:

With recent versions of ext4 (2.6.29 and later), you can mount any ext2 or ext3 filesystem as ext4 without any changes. You must use tune2fs to enable the new ext4 features:

# tune2fs -O extents,uninit_bg,huge_file /dev/DEV
# e2fsck -f /dev/DEV

Once you have enabled extents a former ext2 or ext3 filesystem, it is an ext4 filesystem and cannot be reverted to the old format.

But note that

Some ext4 features cannot be enabled on an existing ext3 filesystem.

and that you should see the Ext4 Howto for more details.

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If you overwrite your partition with the ex3 image, it will contain an ext3 file system.

But you can convert an ext3 FS to ext4 by tweaking sone of its parameters:

tune2fs -O extents,uninit_bg,dir_index /dev/...

After this, the FS is guaranteed to be mounted by the ext4 driver - which then makes use of the TRIM function.

But it might be that a recent enough kernel uses the ext4 driver nevertheless - I am just not sure. CMIIW.

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