HOWTO: Tweak your ext3 filesystem for a performance boost

[BrowneR]

from what I gather a journalized filesystem is not so much for data integrity but for speed of recovery after an unclean dismount.

I too have been using ext2 on my partitions for a year or so to enable easy data sharing with windows (which i seldom use by the way ). It is all running fine although disk access does seem to be a bit of a bottleneck for me performance wise.

I guess things would only get worse if I converted to ext3 and added all the journalling overheads?

Those benchmarks you are doing [USER]esaym[/USER] sure would be interesting to see.

[BrowneR]

After a quick bit of googling i found this benchmark of the most common linux filesystems. It seems fairly complete and the testing technique looks to stress the filesystem under various conditions.

ext2 seems to compare favourably with the more exotic xfs/jfs and so it seems logical to me that if you want some extra speed (possibly at the expense of crash recovery?) then convert from ext3 back to ext2 by removing the journal altogether. this way you still have a very well supported filesystem and some extra speed. possibly not the best idea for large disks as fsck times will increase dramatically in the case of a unclean umount.

[esaym]

I am aware of the benchmarks by Justin Piszcz. They seem very well laid out and professional. However I am really not so interested in which filesystem can create 10,000 empty files the fastest. I plan on simply filling a 30gb partition about 45% full will typical desktop type files and then benchmarking how long it will take to copy all of the files out of that partition. Then I plan on repeating it again only filing the partition up to about 90% and then doing it again, this way it will test for how well fragmentation is handled.

Not the most professional method but I think it might shine some light. I just got to find time in the next few weeks to do it.

[esaym]

Well today I was digging around looking for some ideas on how to run my benchmarks and I came across lots of sites that have already done lots of testing. It seems the more I research and think I have found the fastest filesytem, then the next thing I know is I come across a benchmark that flips my conclusions.

http://linuxperf.sourceforge.net/iozone/iozone.php

http://kerneltrap.org/node/1054

http://fsbench.netnation.com/
Looking at the combined tests and skipping to the total time numbers on the right of the graph shows jfs to be pretty strong most of the time. Even though reiser has some of the highest read speeds it falls short in some other areas.

However right when you start to think jfs is the way to go you see this:

I've been reading good thing about JFS and decided to try it on my spare 10G hard drive. Before each test I erased and created new partition with and used appropriate mkfs command to create jfs/reiser/ext3 file system.
I used reiserfs and extfs drivers included in stock 2.4.22 kernel. I downloaded latest JFS sources at that time (more than one week ago) and recompiled kernel.

test1: "time tar jxvf linux-2.4.21.tar.bz2"

JFS(worst) reiser3(best) ext3
real 2m57.296s 0m48.341s 1m22.625s
user 0m29.900s 0m30.470s 0m29.920s
sys 0m3.140s 0m3.900s 0m3.240s

test2: "time rm -r linux-2.4.21"

JFS(worst) reiser3 ext3(best)
real 1m48.794s 0m2.143s 0m0.627s
user 0m0.060s 0m0.030s 0m0.010s
sys 0m0.660s 0m0.880s 0m0.470s

test3: "time cp /mnt/somewhere/700MBfile.bin /mnt/test_partition"
(copy one large file from fast 80GB disk to 10GB test disk)

JFS(worst) reiser3 ext3(best)
real 4m29.414s 1m7.493s 0m58.911s
user 0m0.170s 0m0.130s 0m0.080s
sys 0m7.010s 0m7.800s 0m6.730s

Results speak for themselves. With work I do as a desktop user (uncompressing, compiling, and deleting large source trees and doing some multimedia stuff) JFS might be wrong choice. I'm using reiserfs and I'm quite satisfied with it.

regards

According to the comments left here: http://linux.slashdot.org/article.pl...539235&tid=198

xfs and jfs are for enterprise solutions and do not take well to power loses, unclean mounts or kernal panics. Apparently ext2&3 were made just for consumer level desktops.

I think I will stick with ext2 for now. Once I get ubuntu up on my desktop it will be interesting how long a fsck will take on the 200gb disk in it vs the 40gb one in my laptop right now.

[esaym]

Well just an update I'm moving back to ext3 lol

I have been having some lock up problems on my desktop: http://ubuntuforums.org/showthread.p...00#post1904500

Usually what happens after it locks and I force it off is all the small config files for kde that were loaded into memory get unattached from the inodes. fsck will run and find them but since there is no journal to tell where the file goes it gets dropped into your lost+found folder. So now you have a config file with a random number as a file name and you don't know where in the world it goes. In the mean time you have all your themes, fonts and generally your whole desktop screwed up (visually). I had a really bad lock up this morning. I logged off and then logged back on and got a corrupt screen (I think it my video card) and I had to force it off. Messed up a bunch of stuff and I have spent 2 hours trying to get my desktop visually back to the way it should be but I haven't had any luck.

In summary I am going to move all my computers to the writeback mode just like this excellent howto says

Live and learn

[esaym]

Ok ext3 with data write back mode passes my data integrity test. I just did a bunch of "horrible" things to it like pulling the plug, opening 20 applications and then forcing it off ect. fsck never even ran. Everything seems fine.

[raul_]

Hummm...oh well writing from the Live CD here i get this error when i tried to reboot:

/bin/sh : can't access tty ; job control turned off

and then it jumps to a built in shell and i can't do anything with it, not even undo the procedure...

stuck big time

[raul_]

Back in business. Mounted my drive with the live CD and undid the changes there. I noticed that my filesystem is actually ext2 (don't know how that happened, maybe because i haven't performed a clean install since Hoary?) bah...now i want ext3

[raul_]

Ok, converted to ext3 and now the tweak works. I can't see no real improvement though. I actually did this for fun now i'm afraid that i'll lose my data with a power failure maybe i'll switch to ordered journaling again

[BoomerTPU]

Hi I'm a linux newbie and I've read your guide.
I'm running Ubuntu 6.10 on an old P3-m 128mb ram machine. My problem is that when I type in the "sudo kate /etc/fstab" I get an error message saying something about the function kate doesn't exist. Do I have to install anything else before following this guide ?

Thanks for the help!