More timings populating a mailbox
ross at biostat.ucsf.edu
Sun Dec 31 17:17:22 EST 2006
On Mon, Dec 25, 2006 at 10:59:36AM -0500, Wesley Craig wrote:
> These are interesting results. I encourage you to make an entry in
> the Cyrus Wiki about the work you've been doing. As an additional
> filesystem option, we've found that IMAP on reiser improves
> significantly with the notail option. Good work.
notail is a lot faster: here are some new timings, with some old ones
20 171.0 Reiser vanilla
20 232.1 Reiser + fakesync
20 199.8 Reiser notail
20 356.4 Reiser notail + fakesync
40 514.7 Reiser notail + fakesync (just to check scaling)
20 185,1 ext3 vanilla
20 267.3 ext3 noatime
20 393.2 ext3 noatime + fakesync
Reiser with fakesync has much more variable times than the others.
Reiser also has a nolog option, which I didn't try. There are quite a
few more knobs to tweak for all the filesystems.
The first time I tried Reiser + notail + fakesync the mailstore got
damaged; I was unable to determine the exact problem (I have a feeling
logging from the chroot I was running in didn't work), or to recover
from it. I wiped the directories and started over. No problems on
the 2nd attempt.
ext3 still seems the better choice than Reiser for these tests:
* No corruption during testing.
* slightly faster for migration (with fakesync)
* faster for safe use (w/o fakesync, though the timings above aren't
of operations typical of daily use)
* lower variance of times.
If I have the time, I'll try to update the wiki--can anyone change the
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