Why Redhat Choose ext3 For 7.2

mz001b writes "There is an interesting article from RH posted on LinuxToday discussing why they chose ext3 over the other available journaling filesystems (ReiserFS, xfs, jfs,...) for RH 7.2"

Comments

Experiences with ReiserFS

[DaveWood]

As our partition continued to grow, from 13GB to 37GB to 50GB and now 100 and soon to grow again (and there are hundreds of thousands of files), somewhere around the 50GB mark ext2 started to get a little overburdened.

Linux has never crashed on me without a hardware problem causing it (not an exaggeration), but that doesn't mean we haven't had plenty of hardware problems, and each time there was a failure, the fsck would take 30-45 minutes. My first thought was ext3, but... heh. It was always grayed out in the kernel config menus. Not a good sign. ReiserFS on the other hand was immediately available.

Of course, you don't trust your data to something without being damn thorough about it, so I did a bunch of tests on staging servers (which went great) and I spent a lot of time reading Hans Reiser, who impressed me considerably as a smart person with a lot of good ideas. We made the move this spring and have had zero problems with the filesystem during normal operations. Zero. It's blazing fast on our tests, it appears to scale beautifully, and if I go down, I have no wait time anymore coming back up.

Of course, I keep up with the kernel changes and upgrade when I see updates relevant to the filesystem.

It's not a perfect package, but nearly. Its consistency checker/repair tool (reiserfsck) is not finished (as its messages vigorously warn). Now, remember, this is not the same thing as e2fsck. You are not using it in the same role, its purpose is much more specialized (disaster recovery), so the significance is different. Still; we came to use it during several of the many times high-speed SCSI chomped on our asses and corrupted data. We have backups, of course, but I wanted to see what the tool was capable of. In several cases it was able to successfully rebuild the filesystem, very slowly, with --rebuilddb, but in several other cases, the tool would dump core, which, if you were one of those fools without a backup, would leave you stranded.

Even in this, however, I was reassured; the maintainer of the tool answers emails quickly and was eager to try to troubleshoot the problem. I thus have no doubt that it will quickly mature into something quite good. It's just not there at this moment.

On the whole I would say I'm extremely happy with ReiserFS; we've punished it here pretty brutally and it's passed every test. I don't have any experience with ext3, but anecdotally I'm told it's less mature. Still, I have nothing against it. I can only comment that I hope Redhat's upgrade process from 7.1 to 7.2 will at least take reiserfs into account, instead of breaking the way it did from 7.0 to 7.1.

Easier Partitioning

[GroundBounce]

I use Partition Magic on a regular basis to manage my partitions, resizing and moving them around as needed. (I know, it's commercial software, but it's one of the more useful pieces of commercial software out there, especially if you like to change things around a lot on your systems.)

PM supports ext2 but not any of the newer exotic journaling file systems like ReiserFS or xfs.

The fact that ext3 is comatable with ext2, and can be converted back and forth is a welcome feature for those who use PM to manage their partitions.

Re:Man, I can't imagine...

[Anonymous Coward]

You might want to mention that Reiser has his own backers (SuSe and others).

ReiserFS has also had a much more public 'beta period' than ext3*, which probably has garnered it more fans, but also has brought out lots of problems which may have turned some people off.

*Reiser has been very public about asking people to try his filesystem. Tweedie has almost discouraged regular users, while according to the article, RedHat has done a bunch of controlled QA testing and 'closed' betas.

Re:Who out there has actually done real research?

[randombit]

ReiserFS, but comparison, has never failed me. I've used it extensively on production machines under 2.2 and 2.4, and been using knfsd since 2.4.6 was released.

Well, we had many problems here with ReiserFS/RAID0 and NFS, even after all the NFS and RAID problems were "fixed". Then we went back to ext2. Which works.

We're thinking about maybe going to ext3 (and not because Redhat told use to do so - we're using Mandrake, and maybe going to Debian sometime). But rather, because if something goes wrong we can do a simple fall back to ext2 and we're working again.

So, yeah, try what you think will work, be it ext2, ext3, XFS, JFS, ReiserFS, or FAT16; if it doesn't work, try something else. :)

So, where is it?

[Pflipp]

(Sorry if I be a little short-sentenced. I just wrote a whole story then Mozilla went nuts so now I am doing it again.)

Two things: First, with 2.4 we were `promised' journaling and devfs. Both are still marked experimental, and of journaling, only ReiserFS is included as an appetizer, but the subsystem is still heavily in development. Some smaller things that were supposed to be improved at 2.4 are also still marked experimental. My guess is that most people -like me- are still using ext2 and device nodes, silently but eagerly waiting until journaling and devfs (and these other smaller things) get marked `stable' (by the proper authorities ;-), and that, as a result, journaling and devfs will really become mainstream when 2.5 is in good sight. So while 2.4 was supposed to bring us these two big features, in reality, well, it doesn't. Yes, I know, it provides the basis, is being worked on, can be obtained by patches etc. etc., but that doesn't practically make it much difference from 2.2, because as I said, for what I guess, most people still aren't encouraged to take the step to a journaling filesystem.

Second: think GCC-2.96 (IIRC). RedHat has the power to shape the Free Software market a little bit the way they like it. With the inclusion of the compiler marked as GCC-2.96 they have practically released a GCC version without involving the GCC team. When RedHat issues a kernel that does ext3 (not just as an option, but as a default feature), I guess at least some of the results are the same as with the GCC-2.96 case. Although maybe this time not `faced with the facts' (that RedHat issued GCC-2.96), but merely `by popular demand' (from other distro's that want to use journaling by now), there will be some pressure on other distro's and the kernel developers to get journalining in.

Hmm. Maybe I'm really exaggerating the case. And do keep in mind that I'm not mad that I don't `get what I'm promised' or something like that. It just makes me nervous that I can't find ext3 anywhere in my fresh kernel sources (2.4.7; debian testing doesn't have 2.4.8 yet but I don't think the differences are that big wrt journaling and `marked experimental' stuff AFAIK from the changelogs) while the ext3 patches for the 2.2 series _are_ in the distro. And I really can use that stable VM of 2.4; earlier on the GIMP crashed my box, now it just crashes itself when loading huge things. I do get complete keyboard blocks once in a while, but no trashing anymore, and hey, that's what the reset button was built for, right?

Which brings us back to journaling.... Oh well ;-)