Hi,
Andrew Morgan wrote:
On Sun, 6 Nov 2005, Michael Loftis wrote:
I'd also be VERY interested since our experience was quite the
opposite. ReiserFS was faster than all three, XFS trailing a dismal
third (also had corruption issues) and ext3 second or even more dismal
third, depending on if you ignored it's wretched large directory
performance or not. ReiserFS performed solidly and predictably in all
tests. Not the same could be said for XFS and ext3. This was about 2
yrs ago though.
Make sure that you format ext3 partitions with dir_index which improves
large directory performance.
... but decreases read performance in general... at least that is what I
found under RH / Fedora!
Look at:
http://www.surfnetters.nl/paul/fs/2/read.png
http://www.surfnetters.nl/paul/fs/tarcopy-read-ext3.png
... to see that reading from ext3 with dir_index enabled takes about
2h15 to read 20 Gb of mail data, while...
http://www.surfnetters.nl/paul/fs/read-plainext3-reiserfs.png
http://www.surfnetters.nl/paul/fs/2/read2.png
... without dir_index it takes only 15 minutes! ReiserFS was a bit
slower for me with reads, but faster in writes. ReiserFS was also
predictable in writes, where ext3 was slow(er) on large directories, but
not that dramaticly. (I have graphs of that too.)
http://www.surfnetters.nl/paul/fs/2/write.png
BTW: I found that chaning dir_index with tune2fs didn't work as
expected. If I disabled the dir_indexes, even after a forced fsck,
performance was still slow. Enabling didn't give predictable results
either: I had to specify it with mkfs.
I posted this to the RedHat list once, no-one replied. I decided that my
tests where satisfied my questions for what fs to use under RedHat 4 for
our NG mail platform... (ext3: supported, lots of (coroner) tools, fast
enough, available in the stock kernel (if you need RH), ... and ReiserFS
3 already has a successor, ...)
Paul
P.S. I also compared FreeBSD's UFS2 under 5.3. I should maybe try again
with 6, since that release should have improved filesystem and disk
performance in general. We use FreeBSD now, it's a pity we move to RH
for this, but "Dell hardware" maybe says enough.
P.S. You can look at the graph's including some comments on
http://www.surfnetters.nl/paul/fs/2
and
http://www.surfnetters.nl/paul/fs
(more rubbish)
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