[ Thanks to Michael Larabel for
this link. ]
“Over the past week there has been a lot of talk about
the EXT4 file-system following the announcement that Google is
migrating their EXT2 file-systems to EXT4. Their reasons for this
transition to EXT4 are attributed to the easy migration process and
Google engineers are pleased with this file-system’s performance.
However, as we mentioned in that news post last week and in many
other articles over the past weeks and months, EXT4 is not as great
of a contender as it was in the past, well, for some tests at
least. The performance of the EXT4 file-system commonly goes down
with new kernel releases and not up, as kernel developers continue
to introduce new safeguards to address potential data loss problems
that initially plagued some EXT4 users. For our latest EXT4
benchmarks we have numbers that show this file-system’s performance
using a vanilla 2.6.28 kernel (when EXT4 was marked as stable) and
then every major kernel release up through the latest Linux 2.6.33
release candidate.“We had installed Ubuntu 9.04 for this testing and left
everything in its stock configuration except for swapping out the
kernels. The kernels we used for testing were all obtained from the
Ubuntu kernel mainline PPA. These kernels were the 64-bit versions
of the 2.6.28, 2.6.29, 2.6.30, 2.6.31, 2.6.32, and 2.6.33-rc4
releases. We tested out a Linux 2.6.33 kernel release candidate as
Phoromatic Tracker running in our kernel test farm had found a few
performance drops on a solid-state drive with the EXT4 file-system
in the current kernel development cycle, with new results being
uploaded daily via Phoromatic at kernel-tracker.phoromatic.com. The
EXT4 file-system mount options were left at their defaults (though
at the end of this article we also have some results using the
nobarrier mount option).”