[Dovecot] Performance, dovecot vs tpop3d

[Nate]

At 06:07 PM 1/30/2007, Kenny Dail wrote:

>I'm curious about your setup, what are the times when you do that with tpop3d?
>17K messages makes for a huge maildir, what OS, filesystem, and how is
>it attached?

I just ran the test on tpop3d, it's a production server, so naturally 
being early evening the server load is much higher right now, so the 
#'s are a bit off from the earlier testing times.

tpop3d takes ~60 seconds to build the index (right now, dovecot takes 
about the same).   each connection afterwards returns instant 
results.  I'll do more thorough testing tomorrow when load is down.

The machine is a 1.6ghz Athlon
512mb ram  (swap is never dipped into)
Local reiserfs filesystem
    linux software raid-1 using 2 disks
    disks are sata 7200 rpm seagate enterprise

tpop3d is not configured to store the index on disk, so apparently it 
does it all in memory; however, oddly enough, a restart doesn't slow 
down the next login so it must have a cache file somewhere i'm 
overlooking.  it's late and i'll check it out tomorrow.

One significant difference I just noticed between tpop3d and dovecot, 
is tpop3d scans the directory and builds it's index directly after 
the password is verified and before any commands can be 
issues.  Dovecot begins building at the same time; however, allows 
commands.  A LIST command in dovecot will not output results until 
the index rebuild is complete.  I don't think this has any impact on 
performance server-side, but might prompt something different to 
happen client side.  Unsure.

Perhaps another test i'll run, just to compare apples to apples 
tomorrow would be to use a memory index with dovecot as well, and see 
if that drops the I/O load to the same as when tpop3d is running.