Re: Moving /tmp to tmpfs makes it useless
2012/5/27 Adam Borowski wrote:
> I think that box had jfs, but other filesystems are no different: for
> example, ext* will fsync() during a rename() call behind your back even
> if you don't request it, forcing every file to hit the disk
This is easy to check:
$ cd /path/to/tmpfs
$ touch 1
$ time for i in `seq 10000`; do mv $i $((i+1)); done
real 0m9.760s
user 0m2.727s
sys 0m6.773s
$ cd /path/to/ext3
$ touch 1
$ time for i in `seq 10000`; do mv $i $((i+1)); done
real 0m9.624s
user 0m2.679s
sys 0m6.877s
I don't see major difference. Both tests gave 9.5-9.8s range between runs.
Maybe your filesystem is to blame?
> So don't tell me real filesystems are "almost as good" as tmpfs
Tests tell you that. :)
Actually real filesystem is not just "as good", it's better, because it
does not eat memory and slow down other running programs when
writing to disk.
--
Serge
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