Ext3 to ext4 /home upgrade

DREMA · 2009-03-18 01:51:49

Hello folks,

I'm thinking on upgrading my /home ext3 partition to ext4, I already read about the new features and performance improvement, also about the little problems, and the bug about the data loss, it not being a problem to me 'cause I have an UPS.

So, do you recomend me to upgrade or wait a little more for any important problem being right now, etc etc.

Also, how do you recommend me to do the switch;
a) upgrade the ext3 partition to ext4
b) backup everything format to ext4 and copy back

Any trick to increase permormance, noatime, data=writeback, etc etc

Thanks for your opinions and excuse my grammar.

Ranguvar · 2009-03-18 03:01:07

All info on performance tricks, etc. can be found in the ext4.txt file in the Documentation folder in the kernel sources.

http://git.kernel.org/?p=linux/kernel/g … xt;hb=HEAD

ext4 is a stable, solid FS that has been in the kernel for two years or so now, even though it's only recently been marked stable.

As for the data loss, it's not a bug. Here's the lowdown. See, *most* filesystems behave in such a way that data is comitted to disk, practically guaranteed, in a very short amount of time. XFS, ext4, and Btrfs all perform delayed allocation in order to be faster. Apps that have been written according to the POSIX standard will be fine with ext4 and those other filesystems. Some apps, however, are written in such a way that if there is a sudden power loss (if the ext4 filesystem suddenly dies), data might be truncated, usually to 0. This is a bug in the _apps_ - the standard makes no guarantee that the filesystem works like ext2/3, ReiserFS, JFS, etc. But since there's a good number of buggy apps, Tso is working on some ugly hacks to make this scenario less likely. What you can do right now is add the 'nodealloc' mount option to your fstab. This will disable delayed allocation. Boom, no more 'bug'. Lower speeds, but still faster than ext3. Kernel 2.6.30 will likely have more efficient hacks that can let you have partial delayed allocation.

Durr. Just read that you have a UPS. So, you're good, most likely

Although, I would only really recommend ext4 if you have particular need of its features - fast fsck, fair performance increase (you likely will not notice it outright), barriers (makes data even less likely to go *poof*, but there can be big performance losses, and cannot be used with device-mapper (LVM, LUKS)), file # limit, etc., OR if you are planning on setting up a new /home anyways and want to spare trouble later. If you're already on another FS and would otherwise not need to do any switching or anything, I'd stick with ext3 for maybe a year.

bwalk · 2009-03-18 07:08:43

There's a list of those buggy apps? Maybe someone wants to do some bug fixing.

zyghom · 2009-03-18 08:14:26

DREMA wrote:

Hello folks,
Also, how do you recommend me to do the switch;
a) upgrade the ext3 partition to ext4
b) backup everything format to ext4 and copy back

always backup for such actions !
backup should be even on routine basis - not only before this

Zyclone · 2009-03-18 12:41:26

I followed the guide on the arch wiki, and converted my ext3 to ext4. I didnt have any issues with converting over. I would reccomend backing up your data befor hand, its always good judgment to do so.

http://wiki.archlinux.org/index.php/Ext4

ammon · 2009-03-18 16:07:14

Could ext4 be converted to btrfs?

dyscoria · 2009-03-27 10:30:37

ammon wrote:

Could ext4 be converted to btrfs?

No.

Ext4 is an advanced level of the ext3 filesystem and therefore supports the possibility of conversion.

btrfs is an entirely different filesystem altogether.

DREMA · 2009-03-30 20:45:51

Hey Ranguvar thanks for that, and your right that's not a bug, I had read an article abut that and totally forgot, sorry for adding more fud to ext4.

Anyway, I just move to ext4 and I could say I like it, the access to my files is faster (not that much) and there are not any problems yet. Now I'm testing with some flags in fstab, like noatime, etc, to see if there are any improve.

haxit · 2009-03-30 20:53:41

I didn't format. I just changed from ext3 in fstab to ext4dev.

Arch Linux

#1 2009-03-18 01:51:49

Ext3 to ext4 /home upgrade

#2 2009-03-18 03:01:07

Re: Ext3 to ext4 /home upgrade

#3 2009-03-18 07:08:43

Re: Ext3 to ext4 /home upgrade

#4 2009-03-18 08:14:26

Re: Ext3 to ext4 /home upgrade

#5 2009-03-18 12:41:26

Re: Ext3 to ext4 /home upgrade

#6 2009-03-18 16:07:14

Re: Ext3 to ext4 /home upgrade

#7 2009-03-27 10:30:37

Re: Ext3 to ext4 /home upgrade

#8 2009-03-30 20:45:51

Re: Ext3 to ext4 /home upgrade

#9 2009-03-30 20:53:41

Re: Ext3 to ext4 /home upgrade

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