2009/3/21 Brandon Hilkert <[email protected]>: >> When the disk is 100% busy, then it is the bottle neck. Disks can >> be 100% busy jumping around doing very little I/O. >> >> As Noel suggested in earlier email, try running smtp-sink which >> does no disk I/O at all. If things are still slow, then the problem >> is network or MS-Exchange configuration. > > I found the source. How do I build it in Debian? I realize this is probably > a stupid question, but I don't have tons of experience with Linux.
Wietse has already answered this, but packages are your friend: http://packages.debian.org/search?searchon=contents&keywords=smtp-sink&mode=path&suite=stable&arch=any You'll see it also includes smtp-source, just the thing to use! http://packages.debian.org/lenny/i386/postfix/filelist You should follow Victor's advice and check out the QSHAPE_README: http://www.postfix.org/QSHAPE_README.html That's got general bottleneck-finding advice, so it's widely applicable. Remember that mail is a store-and-forward mechanism. You need to see if it's slow to accept or slow to flush the messages (or maybe both). Then the fix the problem based on what you see. I'd turn off DKIM first to see how much impact it has. I have some raw performance data available from my own testing, you may find it interesting. It has some of my own notes/thoughts about "how to go faster". To anyone reading it, please observe the caveats noted at the top. http://www.anchor.com.au/hosting/dedicated/Postfix_MTA_performance_testing
