The choice of filesystems on Linux is vast, but most people will stick with their respective distributions’ default choices, which will most likely be ext3, but you’re free to use ReiserFS, XFS, or something else completely if you so desire. Things are about to change though, with btrfs just around the corner. To bridge the gap between now and btfrs, ext3 has been updated to ext4, which adds some interesting features like extents, which are already in use in most other popular file systems. Phoronix decided it was time to do some performance checking on ext4.
After testing, Phoronix concludes that ext4 isn’t an enormous leap forward compared to other file systems, but that it did show a performance advantage over ext3 in pure disk benchmarks – but as they state, that only helps if your job is to run disk benchmarks day-in, day-out (quote of the day, I must say). However, that is not to say that ext4 isn’t worthwhile – there are more important things than raw performance when it comes to file systems.
EXT4 is clearly a significant improvement over EXT3 when it came to the pure disk benchmarks, however, in the real world, saying better performance should not be used as a reason to replace your existing EXT3 or XFS partitions. In our tests that cater towards Linux desktop users and gamers, EXT4 hadn’t delivered a sizable quantitative advantage. That’s not to say though it’s not worth switching to EXT4. EXT4 is more scalable, more efficient through the use of Extents, supports larger disk capacities, can handle twice the number of sub-directories, is capable of handling online defragmentation, and there is improved reliability via journal checksums. What perhaps is more important is that with the addition of these new features, the performance hasn’t regressed. Also, when testing the EXT4 file-system, we hadn’t run into any problems with stability, file corruption, or any other issues.
Ext4 has been available as an option on Fedora for a while now (append the
ext4 boot parameter when booting Anaconda), but for the rest, no major distributions are shipping it yet. It will become part of the next Linux kernel release, so we may see an increase soon enough. Mostly, however, as Phoronix notes, adoption of ext4 will depend on how fast btrfs becomes stable and well-tested.
I’d be really curious to see how the performance of whole disk encryption is affected by filesystem choice. I have a 1.5 TB RAID5 (4x500GB SATA2) entirely encrypted using dm-crypt and dm-raid with XFS on the RAID. I used to have the entire system system encrypted but the performance hit was too painful. It would be interesting to see if the filesystem choice would have much impact on that.
Phoronix is on the ball! With all their recent benchmarks I consider them one of the best places on the net to get good third party information. Keep up the good work
The disk i/o benchmarks were certainly interesting, and worth reading the article to see. But when they started throwing lzma, bzip2, lame, video games, and other processor bound “benchmarks” at these filesystems, I went… “what”? They could have made something out of the video game benchmarks, maybe, by checking the time to start the game and load a level, rather than reporting the FPS. If the FPS is affected by the filesystem, its time to find a new gaming house, not a new filesystem!
Looks like ext4 closes the gap with XFS, or now beats it significantly, in all but that surprising 4GB random delete phase. Deletes used to be a real Achilles heal for XFS, and I know the Linux XFS devs put a lot of special effort into improving that situation. But since it is also slower than ext3 in this phase, I suspect something else is going on.
Beating XFS by 25-30% on the 8GB sequential read and 4GB sequential create phases is particularly notable, since large sequential reads and writes were major design goals for XFS.
And all that with the significant additional integrity guarantees that the default “data=ordered” mode (and, I believe, journal checksumming) provides over XFS. Impressive work by the ext4 guys, indeed.
Edited 2008-12-03 23:48 UTC
again no love for JFS and yeah really, whats unreal tournament in 1280×1024 got to do with disk benchmarks.
If people wanted extents they’d be using a filesystem like JFS or XFS already.
I fail to see the need of ext4 to ‘bridge’ the gap until BTRFS arrives.
Someone had an itch to scratch, so be it.