OS and Software > All Things Unix > Opinions on XFS vs JFS

Opinions on XFS vs JFS

If raw throughput is your main concern, I guess reiserfs4 is the "fastest". But XFS is faster at some things. It depends what you'll be using it for/expecting out of it. I personally like the stability/known recoverability of ext3, so I stick with that on Linux systems.
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"The Dude abides."

reply to Ted
Be very afraid for your data if you use XFS. Not sure about JFS but XFS does not handle crashes or power loss nicely. You will experience corruption and data loss. Ext3 is the safe way to go.
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reply to Ted

reply to Ted
XFS with the addition of write barriers handles power outages much better than it used to. I would choose XFS over JFS due to the fact it has been tested more and has better tools available.

And no, I wouldn't touch Reiser4 -- performance is all over the place, and it also reportedly gets fragmented much more quickly than other filesystems.

reply to Ted
What is your goal? Speed or reliability?

I'm a filesystem nut and I estimate to have spent more than 500 hours of my life just testing filesystems in poweron, poweroff cycles, performance, fragmentation over time, etc etc etc. I've installed and ran Linux off every filesytem that it's even remotely possible to do it, including NTFS root. I've learned almost every lesson there is to learn about Linux filesystems, almost all of them the hard way. I'd be happy to help you choose a filesystem and hopefully save you time and pain and regret a month down the road.

XFS has GREAT performance when manipulating files of any length, but SUCKS at metadata operations. If you regularly need to create or delete a large number of files (of whatever size -- just a big number of them), XFS is not for you. XFS easily fills up its logs and then metadata operations are dog slow and the system response drags down as the log is processed. Increasing log size by mkfs.xfs -l size=128m helps DRAMATICALLY. I highly recommend doing this for XFS volumes. Also, mounting XFS volumes with the option logbufs=8 will help with momentary surges of metadata activity too by allocating a larger cache for holding the journal in memory.

JFS has great reliability and pretty decent performance all around. I'd compare it more to the ext3 type -- not "excelling" or "dominating" in any performance aspect, but definitely being rock solid. It is the filesystem that I've tested to BEST withstand 200 random resets without becoming completely trashed. That's right... better than ext3 with full journaling mode. Downside? Its community seems to be fading. There's less and less knowledgeable JFS people around to answer questions, so if you ever end up with a JFS volume that has suffered so much damage that binary data recovery is necessary, it's MUCH harder to find someone that understands the structure of the filesystem than , say, ext3 or even XFS.

Reiser4 is fast on systems with fast CPU's, which you do not qualify for. reiser4 on your system will be highly CPU bound. Its stability against random resets is second to JFS, but it does not repair well. That is, when the structure is actually damaged, don't expect fsck.reiser4 to help you any more than catting random bytes into your drive in hopes of a miraculous coincidence. Its other downside is fsync performance. Reiser4 has NOT implemented fsync() so whenever the sync of a file is requested, reiser4 will sync the entire drive. That's right. Saving a vim document calls fsync, which will flush all your unwritten disk buffers to disk before allowing vim to exit, even if there's 400MB of unrelated stuff in write cache waiting to be flushed. Many people disable fsync() altogether by putting together a .so lib that replaces fsync() in glibc with "return 0;". The other downside of reiser4 is BEWARE OF NEW OR UNTESTED KERNEL CONFIGURATIONS! There seem to be SEVERAL kernels that are a no-no when combined with reiser4 (truncation to nearest 4kb, small files are just filled with 000000000000, files disappearing, etc). DO NOT ATTEMPT TO PATCH REISER4 ONTO ANY KERNEL BUT THOSE LISTED ON FTP.NAMESYS.COM! Even if it "seems to patch cleanly", you will probably end up paying dearly!

I hope that's more than you ever wanted to know about filesystems. Please ask if you have any more questions. I love filesystems and can talk about them all day if you don't stop me!
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reply to Ted
Check this:
»linuxgazette.net/102/piszcz.html

This is also interesting »www.cs.wisc.edu/adsl/Publication···sp05.pdf

reply to jdong
Wow! Thanks so much, I found the info very interesting. I made XFS my filesystem for root (boot is ext3) and the performance increase is noticeable. It just seems quite a bit snappier on i/o, throughput also seems to have increased.

reply to scooby

reply to jdong

Thanks for the input! I'm sure there's no easy way to convert existing installs, but for new installs I might try JFS. While I wouldn't mind more speed, I'd choose reliability and recover ability every time, for this box.

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reply to Ted
Yeah, the easiest "converting" routine I've been able to come up with is find a bigger drive, format it reiserfs or ext2, rsync to it (-avx --partial /. /mnt/.) reboot into a livecd, remake the drive and reverse the rsync.

It's like a good afternoon's work on a decently sized drive
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reply to Ted
I've been in the XFS camp for a while.. it's a great filesystem.

I tried out reiser4 a while ago, but I found that it was too quirky and became fragmented far too quickly.

Good point -- that's a downside I forgot to address with reiser4. Its fantastic, 100x-better-than-others (ok, slightly exaggerated) performance will quickly degrade into "a bit better than others, comparable to reiserfs" within two months of heavy usage.

It needs a repacker to stay in tip-top shape, which is nowhere to be found nowadays (removed from reiser4 due to stability issues)
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reply to Ted
My choice? VxFS. Hasn't let me down yet, and I've been managing many many hundreds of TB's using it for a very long time.

It's part of the (free!!) Storage Foundation Basic available here:

»www.symantec.com/enterprise/them···=sfbasic

... excellent ...

reply to Ted
The only problem I know of with JFS is that it ss undermaintained / unmaintained; whereas XFS is more maintained.

I don;t know about any technical issues with JFS; I do know because of the sequence of the jounaling in XFS it can result in data loss.