Has anybody tried ext4?

[Schwinni]

Hi all,

I patched my gentoo-sources-2.6.27 with the latest ext4 patches, so that ext4dev is changed to ext4:
http://www2.kernel.org/pub/linux/kernel/people/tytso/ext4-patches/2.6.27-ext4-2/

The patch ran fine and I also have built ext4 into kernel.

Now I'd like to use ext4. Has anybody tried that already?

With regard to the ext4 documentation it should be easy:

[nixnut]

Moved from Kernel & Hardware to Unsupported Software.
unsupported stuff, so moved here
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[aronparsons]

You shouldn't need to append any options to mkfs.

I've been using ext4dev for months with the latest patches for 2.6.25 and 2.6.26 applied. It's been stable and is much faster than ext3. fsck is much quicker too for those unexpected shutdowns (e.g. failure to resume from suspend correctly).

I say give it a go, but make sure you have a good backup first. I went the route of creating new logical volumes with LVM and moving my data over instead of upgrading my ext3 partitions. I had the disk space to do this (1TB RAID5), but if not, I believe you can just mount as ext4, but you then lose backwards compatibility.

[Schwinni]

Thanks for your reply.

Unfortunately I don't have any disk space over.

I already checked the 2 relevant partitions and they already have an inode size of 256 bytes.

In order to use extents I have to run tune2fs -O extents -E test_fs /dev/<partition>, right?
Or is it tune2fs -O extents /dev/<partition>, because I have applied the patch to remove the dev state?

Can I run that although the partition is mounted?
If not, which LiveCD/DVD should I use?

[Schwinni]

I did it.
For "tune2fs -O extents" the partition can stay mounted.
Then changing /etc/fstab and a reboot...

The only thing I wonder is the first line of "dmesg | grep EXT":

[asturm]

I've put together an ebuild based on 2.6.27.3 + gentoo patchset + the ext4 patch:

http://rapidshare.com/files/156778164/ext4-sources-2.6.27.3.ebuild.html

Use at your own risk! This is not yet tested with an actual ext4 filesystem, but compiles fine and boots successfully.

I do have an ext4 partition at home (not to confuse with /home ) but my laptop runs on reiserfs, so I can't test it myself for now.

[Schwinni]

Since your ebuild does exactly the same like my manual patching (gentoo-sources-2.6.27 patched with 2.6.27-ext4-2), and my setup works with / and /home mounted as ext4 I would say that the kernel built with the ebuild will work also...

[asturm]

Using .3 though corrected a v86d segfault with the ext4-patched kernel image.

I'm going to try that out with my 1TB backup fileserver once I'm setting it up. ext4 is exactly what I need there.

[Schwinni]

gentoo-sources-2.6.27-r1 just reached portage and the patch ran fine.
That should be the same like your ebuild.

So, the ebuild should work fine.

[Jimmy Jazz]

[asturm]

It is, according to his first post.

[Schwinni]

[Jimmy Jazz]

[asturm]

I'm trying it out myself now, let's see if it shows the same message...

[Schwinni]

Yes, perhaps the message comes because I didn't set "-E test_fs" with tune2fs.
On the other hand, that shouldn't be needed because of the patch.
Weird...

[asturm]

I do not get that message. Did a "tune2fs -O extents /dev/sdb1" just like you and get the following output:

[Jimmy Jazz]

[Schwinni]

[asturm]

Nothing special, just the defaults.

[Schwinni]

Hmm, I use "defaults,user_xattr".
Gonna set it to defaults and see what happens...

[Grahammm]

I have already converted my /home partition to ext4 and am considering converting my root partition (currently ext3). I am using the 2.6.27-ext4-2 patchset applied to gentoo-sources-2.6.27-r1. But before I convert the root partition, there are a couple of things I want to make sure of first.

1) For safety, I want to have a rescue CD/DVD/USB stick with a kernel (preferably a patched 2.6.27) and e2fsprogs which can handle ext4. Obviously the Gentoo live CDs do not. Are there any live CDs which do?

2) That the root partition will mount as ext4. The documentation says that the ext4 driver can mount an ext3 partition, so I edited /etc/fstab to make / ext4 but after re-booting it still showed as ext3. So i want to make sure that if I enable extents, that it will mount (especially if I have not got a rescue disk which groks ext4)

[boris64]

I'm also using ext4 on all partitions for about a week
now and got no problems yet.

There is just one tiny thing that needs to be resolved to use
it on my root partition.
I didn't find any grub version, that can boot an ext4 root partition (w/o extra /boot).
Is there anyone who found a working patch etc.?
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[sleipner]

[mikkoc]

So, I have 2.6.28 kernel with ext4 support built-in (no ext4dev).

I also have e2fsprogs-1.41.3

What do I need to switch to ext4?
Is it enough to change ext3 to ext4 in /etc/fstab?

I currently have:
/dev/sda8 / ext3 defaults 0 1

thanks

[Schwinni]