EXT2 file system is the predecessor to the EXT3 file system. EXT2 is
not journaled, and hence is not recommended any longer (customers
should move to EXT3).
EXT3 file system is a journaled file system that has the greatest
use in Linux today. It is the "Linux" File system. It is quite robust
and quick, although it does not scale well to large volumes nor a great
number of files. Recently a scalability feature was added called
htrees, which significantly improved EXT3's scalability. However it is
still not as scalable as some of the other file systems listed even
with htrees. It scales similar to NTFS with htrees. Without htrees,
EXT3 does not handle more than about 5,000 files in a directory.
The Reiser File System is the default file system in SUSE Linux
distributions. Reiser FS was designed to remove the scalability and
performance limitations that exist in EXT2 and EXT3 file systems. It
scales and performs extremely well on Linux, outscaling EXT3 with
htrees. In addition, Reiser was designed to very efficiently use disk
space. As a result, it is the best file system on Linux where there are
a great number of small files in the file system. As collaboration
(email) and many web serving applications have lots of small files,
Reiser is best suited for these types of workloads.
With some up and coming distributions starting to adopt or even
offer ext4 support for their flavor of Linux, I thought it would be
appropriate to discuss some of the finer and not so fine points of
ext4, in contrast to ext3. While ext4 is exciting and fast, its not all
fun and games. This may be invisible to most users using ext4, but to
more adept users, there are some things you should know. Keep in mind,
Ext4 is still in its early stages. Also compared is eh XFS file system,
which is still a formidable opponent.
Bonnie++ 4GB Sequential Read :
Ext4’s sequential read speeds are a pretty fast, Reiser4 was a good
deal slower, sometimes up to 30% slower. Ext3’s sequential read speeds
just as slow and many cases losing its crow to Reiser 4. With XFS, we
see performance matching Ext4.
Bonnie++ 4GB Sequential Create
In creating small files, we see, at least this early on Ext4 and
Extt3 being very close, Ext4 seems to edge out Ext3 and Reiser4. In
comparison, Reiser4 tended to fall behind, being a little more slow in
these operations. XFS was better than Ext3 and Reiser4, but still not
up to par with Ext4. Keep in mind, as I said, both Reiser4 and Ext4 are
early in their stages.
Bonnie++ 4 GB Sequential Delete
Ext4 was slated to be faster in this area, and it may be, but not
yet. Ext3 and Reiser4 both beat Ext4 in 4GB deletion, so it will be
surprising if re-tooling of Ext4 can push the rates higher. For now,
its performance was a bit disappointing. XFS edged out all the others,
having the best times for 4GB sequential deletion.
Bonnie++ 8GB Sequential Read :
With sequential read on 8GB, Ext4 pulls out ahead again, but not by
a huge margin. XFS is close behind on speed, followed but Ext3 and
Reiser4.
Bonnie++ 8GB Sequential Create :
In this area, I saw Ext4 shine again, with very good creation speeds
in comparison to the other file systems. Reiser4 and Ext3 are pretty
close to each other, with some instances Reiser4 performing better. We
will see how this stacks up later in the year.
linux file system difference
