What a difference a kernel rev and/or distribution make. If you recall from a previous post, I was unable to complete postmark testing on Ubuntu 9.04 using ext4, and had to recommend against ext4. Now, with the release of Fedora 11 “Leonidas”, a new kernel seems to make a big difference in performance and stability of ext4.
Some other observations before I show any numbers:
- This is NOT the same computer as was used in the previous test, don’t use these numbers to compare between Ubuntu and Fedora. It’s a desktop with a 64-bit Athlon and 1GB RAM. I know, I know… I didn’t have access to the other box. Look at Phoronix.com for a comparison of the two.
- The 2.6.29 kernel seems to have a much better implementation of the CFQ I/O elevator, I only noticed a slight decrease in performance using deadline instead of the increase I usually get with XFS (ext3 and ext4 have always been tuned for CFQ).
- In this version, using my usual (and sometimes unsafe and daring) mount switches didn’t seem to make a huge difference on XFS and none in ext4 or even ext3, Fedora 11 is really a distribution that the developers want you to be able to use without much fussing.
- On all tests, I created XFS with mkfs.xfs -f -l lazy-count=1 -l size=128m /dev/… – this enables the 2 main (and safe) tunings that I believe everyone should follow with XFS. Kinda hard to do while installing a distribution, the Fedora 11 installed wasn’t happy about it. Ubuntu is more forgiving, it lets you boot into the LiveCD and you can manually create partitions before you let the installer do its thing. Convenient for single-root-partition installs…
- “XFS tuned” means mounted with noatime,logbsize=256k,nobarrier (nobarrier is unsafe unless you’re on a UPS and/or have enterprise back end storage).
- “ext3 tuned” means barrier=0,noatime,data=writeback. Used to make a big difference…
- The same disk area was used for all tests
- Scribefire on Firefox sucks compared to Mac- or Windows-based offline blog editors. There are some KDE-based ones but I didn’t want to download 100s of MB of KDE support infrastructure to run a 600K blog program…
|Filesystem||Read MB/s||Write MB/s||IOPS|
|Block writes KB/s||Rewrite KB/s|
- Ext4 shows great promise!
- For sheer MB/s on large files, XFS is still better by a small margin
- If you want to be doing operations on many small files, ext4 is great
- The reworked CFQ scheduler rocks