On Friday 12 November 2004 06:05 am, Tomas Kuliavas wrote: > > Tomas Kuliavas wrote: > >>I think bottleneck is in your filesystem. Compare directory access times > >>on different filesystems. Find the one that can access directories with > >>many small files faster. > > > > This evening I set up a test. I used the same Maildir ~850MB in size > > with 27k messages in my INBOX in each case. I logged into SquirrelMail > > with each user three times, and took the average number of seconds > > before the INBOX folder contents appeared. > > > > Case 1: Maildir lives on an ext2 filesystem within a RAID5 set of five > > disks. This filesystem is then NFS mounted to the IMAP server. Average > > time to display: 41 seconds. > > Case 2: Maildir lives on a reiserfs (Reiser4) filesystem on a RAID0 set > > of two disks. This filesystem is then NFS mounted to the IMAP server. > > Average time to display: 64 seconds. > > Case 3: Maildir lives on an ext3 filesystem on a RAID0 set of two > > disks. This filesystem is local to the IMAP server. Average time to > > display: 37 seconds. > > > > Not at all what I expected. Pretty much everyone was saying that > > ReiserFS was the way to go for many small files, and yet it was by far > > the slowest. Also, the effect of NFS vs. local was small. > > > > I can see that the entire time I'm waiting for the page to return, imapd > > is pegging the CPU, so this might be CPU-bound. However, it could also > > be pegging the CPU simply because the CPU has nothing else to do and can > > dedicate 99.9% of its cycles to the imapd process. I would hope that > > one single imap session would not bring a Xeon 2.8GHz/1GB mem to its > > knees. Even still, I'll be able to compare in a couple of weeks when > > the 2nd processor and another 1GB of RAM comes in for these systems. > > > > Now, I might just write this off and tell users "if you have folders > > with 27k messages in them, prepare for horrid performance", but it's > > just one of those things that you just want to make faster. :-) > > 1. You forgot XFS and JFS. > http://oregonstate.edu/~kveton/fs/page2.php > > 2. maybe fam provide some performance increase > http://www.courier-mta.org/?imapd.html > http://oss.sgi.com/projects/fam/
another thing to consider is that if you were just accessing the maildir for
the first time, your imap server has to build its internal cache (courier
does this, I know). Try accessing the folder with another imap client first,
and then see how it fares with squirrelmail. I have zero issues with
maildir, reiserfs, and squirrelmail (1.5.1-cvs, updated about 2 weeks ago)
-Jeremy
--
Jeremy Kitchen ++ Systems Administrator ++ Inter7 Internet Technologies, Inc.
[EMAIL PROTECTED] ++ www.inter7.com ++ 866.528.3530 ++ 815.776.9465 int'l
kitchen @ #qmail #gentoo on EFnet IRC ++ scriptkitchen.com/qmail
GnuPG Key ID: 481BF7E2 ++ jabber:[EMAIL PROTECTED]
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