Howto Tweak Ext3

Hmm...very interesting, indeed! Thanks for the tips, John. I may have to try this out myself. Would you recommend trying it on my home partition first, since data recovery in the case of a crash is more critical on the root partition?

In addition to detailed descriptions of writeback, ordered, and journal modes this Gentoo site from October 9, 2005 has some interesting results:
http://www.gentoo.org/doc/en/articles/l-afig-p8.xml

"Theoretically, data=journal mode is the slowest journaling mode of all, since data gets written to disk twice rather than once. However, it turns out that in certain situations, data=journal mode can be blazingly fast. Andrew Morton, after hearing reports on LKML that ext3 data=journal filesystems were giving people unbelievably great interactive filesystem performance, decided to put together a little test.

While data was being written to the test filesystem, he attempted to read 16MB of data from another ext2 filesystem on the same disk, timing the results:

The results were astounding. data=journal mode allowed the 16-meg-file to be read from 9 to over 13 times faster than other ext3 modes, ReiserFS, and even ext2 (which has no journaling overhead):

Written-to-filesystem - 16-meg-read-time (seconds)
ext2 - 78
ReiserFS - 67
ext3 data=ordered - 93
ext3 data=writeback - 74
ext3 data=journal - 7

Andrew repeated this test, but tried to read a 16MB file from the test filesystem (rather than a different filesystem), and he got identical results. So, what does this mean? Somehow, ext3's data=journal mode is incredibly well-suited to situations where data needs to be read from and written to disk at the same time. Therefore, ext3's data=journal mode, which was assumed to be the slowest of all ext3 modes in nearly all conditions, actually turns out to have a major performance advantage in busy environments where interactive IO performance needs to be maximized."

Very interesting, indeed, lattup. Can anyone else verify this from personal experience?

I read that article, that was the source of my knowledge of EXT2/3 file system.
I did try it at home and unfortunately I couldn't repeat the "miracle". Maybe my system wasn't busy enough to show how good EXT3 file system is?
I mean, from technical point of view, if system has to write everything twice (once in the journal and once to dump it to file system), how can it be faster?!?!?

Could it have been some bizarre glitch with the 2.4 kernel series? Or perhaps it was specific to that particular system?

You should see what a difference this makes to my VMWare Guests!!! :blink:

It is mind boggling what a difference it made to the Windows guest.

I actually reinstalled my openSUSE 10.2 and during the install I set the writeback option and then reformatted the partitions. Maybe it's just cause I want to, but I can see a NOTICEABLE difference opening programs and copying files. Even running Xgl/compiz/beryl my openSUSE install was approaching Slackware speed. So I booted to my Slackware install and did the tune2fs thing on both the partitions I use with Slackware, made the adjustments to the fstab and the menu.list file, restarted and WOW! It was like I had just put some new memory in or something, even KDE was "snappy" and Dropline GNOME is so fast I swear I saw smoke coming from my screen .

Thanks,
MMYoung

So just to clarify. You dont need to change this option in the / filsystem specificly? You can change this on your /home partition, and the changes will still speed up your system?

So just to clarify. You dont need to change this option in the / filsystem specificly? You can change this on your /home partition, and the changes will still speed up your system?
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If your home folder is on a seperate partition from your root folder, then yes. This has to be applied to each filesystem you're interested in adjusting.

On a side note, I use EXT3 with the Journaled mode. I haven't noticed a speed reduction, but I have noticed that when SUSE crashes, I only lose 4 seconds of work, maximum, because it has a 5 second commit time.

Hi!

Sorry for maybe bumping this topic but I'm having a problem with this...
I configured my /home partition with data=writeback mode and that's working perfectly. My bootlog shows this:

<6>EXT3 FS on hdc1, internal journal
<6>EXT3-fs: mounted filesystem with writeback data mode.

I also try to do this with my / (root) partition, but it seems like it doesn't work. My bootlog shows the following:

<6>EXT3 FS on hda2, internal journal
<6>EXT3-fs: mounted filesystem with ordered data mode.
<3>EXT3-fs: cannot change data mode on remount

I did exactly wat was told in this topic (it's an easy task after all). Does anyone have any suggestions?

Thanx in advance
Greets