Philip Chiang wrote:
Hi, I am trying to make comparisons between ext2 and xfs file system. I ran dbench on my
system with 150 clients on the ext2 file system and on the xfs file system. I ran this
test several times, but the results are similar. On xfs, dbench takes 211 mins to finish.
Where on ext2, it takes 60 mins. I want to ask "why it has such a big difference on
the two file system?" One more note, when dbench is running on xfs, the whole system
tag downs, CPU usage is at 99% all the time, is this normal?
Such a discrepency does not seem right, although at dbench 150 on a 128M
box you are severely
overdriving the memory. Anyone who runs hardware at this load level in a
production environment
is not going to get much out of it. It's a bit like running a news feed
on your palm pilot. If you are
trying to compare performance then compare loads which are realistic.
I am doing some comparison runs here, but I have a question and a comment.
o first, which xfs options do you have turned on? Did you enable
extended attributes and dmapi?
if you did then you really need to turn it off in a comparison - or
get the ext2 equivalent code
going. This would not however account for such a large difference.
o A more apples with apples comparison would be ext3 (without data
journalling) vs xfs.
XFS is going to add the cost of journalling to operations, ext2 is not.
Steve
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