[Dovecot] dovecot vs qpopper performance testing results

[asko]

Hi,

I did some performance testing with dovecot and qpopper, if anyone is 
interested..

Hardware: Dual Xeon 2.8 with HT enabled (dmesg sees 4 cpu-s), 1 GB RAM, 
SCSI RAID 1 with 2x Maxtor Atlas 10K V disks.

Software:  CentOS 4.3, Qpopper 4.08 in standalone mode vs Dovecot 
1.0-0_19.rc6, ext3 filesystem

Mailbox format Mbox, tested Pop3 with PAM authentication

My setup had 15 test users with 15 identical 40 MB mbox files. Each mbox 
had 370 messages, 35 % of them had attachments. So average message size 
is about 110 KB, average attachment size 220 KB.

"rabid" utility is part of postal package 
(http://www.coker.com.au/postal/). Command line, which fetches and 
deletes all the messages from users in the textfile:

rabid -p 1 192.168.x.x ./users -

Resulting fields are:
time,messages,data(K),errors,connections,SSL connections,IMAP connections




Results (only the best one shown):

Qpopper:

1 parallel processes:
12:36,1020,111470,0,6,0,0

5 parallel clients:
12:44,3246,366207,0,13,0,0

15 parallel clients:
13:06,4099,481347,0,48,0,0


Dovecot:
p1:
12:19,3316,367859,0,13,0,0

p5:
12:50,4653,524456,0,34,0,0

p15:
12:56,5063,578889,0,84,0,0




As you can see, Dovecot is faster.. With 15 parallel processes it seems 
to have saturated my 100Mbit/s LAN (578889 kB data in one minute). 
Dovecot had noticeably smaller disk IO and system load was smaller too, 
probably thanks to smaller IO.

Qpopper performed better than I hoped.. It is probably due fast disks of 
the test system, I wouldn't expect such numbers using single IDE disk.

Conclusion: The hardware was too fast for testing, LAN became a 
bottleneck atleast once. The results could be different with different 
mbox structure.. Anyway, I was convinced, Dovecot wins.

--
asko