"As Theodore Ts'o blog advocates using fsync(2) to get around
the rename issue on ext4, one would imagine that it performs much
better on ext4 than ext3. And that leads us to the second part of
the article: benchmarks! What price is there to be paid for
fsync(2) in different scenarios on different filesystems.
"I'll test not only ext3 and ext4 but also XFS, JFS and
Reiserfs. You will notice two benchmarks for XFS, one with the
default options and one with the nobarrier mount option. By default
XFS uses block layer write barriers which can make some operations
much slower. There is also a barrier mount option for ext3 which is
off by default. For ext4 barriers are on by default. Unfortunately
I'm unsure if this barrier option is comparing apples with apples
across these two filesystems though. As btrfs is still so young I
decided to omit it from the benchmarks."