On 12/09/2012, at 7:26 PM, Paul J Stevens <p...@nfg.nl> wrote: > On 09/12/2012 02:10 AM, Simon wrote: >> Hi There, >> >> We are using dbmail-2.2.18 on freshly minted debian squeeze for about 400+ >> mailboxes. The VM (esxi 5.0) it is running on has dual core Xeon E5645 @ >> 2.4GHz with 1GB RAM. >> > > I have no idea how well isolated an esxi VM is. I'm not impressed by > containers like openvz, but hypervisor domains like xen work really > well. Afaik, esxi is more like xen, right? > >> NCHILDREN = 30 > > I generally keep this *really* low, especially on memory constraint > systems. Less is better. Also, make sure you enter different values > below the pop3, lmtp, and imap stanzas, depending on the kind of traffic > you get to handle. This goes for all pre-fork parameters. > >> MAXCHILDREN = 200 > > 1024MB/200 ~= 5MB per client in a fully loaded situation. That is way > too low! Either reduce maxchildren to 100 or double your RAM: 10MB > resident memory per client on average should be enough. And keep an eye > on 'top' to see how much resident memory the imap processes use on avarage. > >> MINSPARECHILDREN = 10 >> MAXSPARECHILDREN = 100 > > Again, way too high. A bandwidth of 2-4 spare clients should be > sufficient, or maybe 2-8. That allows scaling down when daemons are idle. > >> The issue we have with this new install is that it runs into SWAP and just >> (very) slowly fills the swap up.. its load average is 0.01-0.05. > > You will also want to set MAXCONNECTS to something low, like 10. > Overhead for forking new children after reaping older ones is very low. > Keep things neat and clean. > >> Any ideas here, or are my settings above to much? need more RAM? > > More ram never hurts, but try tweaking a little more before you do that.
Thanks for the great feedback Paul. Have made some modifications and things are a little better, plus gave it 2GB ram. Something to note here is that we were not seeing quite the same memory usage with a 32bit VM as a 64bit VM ... something in the configure line needed here? Also, we front-ended dbmail with perdition and that made a huge change to the memory usage - is this because it handles the connections better? Regards, Simon _______________________________________________ DBmail mailing list DBmail@dbmail.org http://mailman.fastxs.nl/cgi-bin/mailman/listinfo/dbmail
