We are going to migrate all our mailservers over to dbmail early next year. Because of this we decided to run a real loadtest. (Not sure about exact number of domains, but something like 20.000 by early next year)
We figured there wouldn't be much load needed to make this test system kneel. It's a: -400mhz P2 -512MB ram -Fedora Core 2 -Postgresql -Single 80GB ide disk (Maxtor) So, at first we subscribed to a few high-volume lists. Nearly not noticable load. So we decided to add all our support, hostmaster, abuse, bounce and so on to it. We could notice a 0.01 load sometimes.. What the heck we thought.. lets forward a copy of all incoming mail to one of the mailservers onto the test box. Now there was a load, but hovering about 0.25 and 50-80% free cpu on average. So, to really make it beg we did this from the rest of the mailservers aswell.. just to see what would happen when overloaded. To our big surprise, that test server handles it quite nicely Load is about 1.5-10. Cpu is 50-100% We see bursts of as much as 20 mails at a time beeing delivered with dbmail-lmtp now. The server lags a little during the bursts, but nothing near what we expected. A typical number of messages delivered per minute is 100-150 mails. In order to handle this load on out Imail windows servers we have 3 high-end dual-cpu servers (scsi) and one quad xeon with a 4gb ram. Granted, those servers do virus scanning too, but even without there would be no way to run it all on a 400mhz P2. Btw, I'm running dbmail 2.0.0. Filesystem is reiserfs3 with default options. I'm also logging at dbmail trace-level 5! So this should account for a good deal of load in itself. Soo.. any errors I should grep the log for or something? -=Dead2=-
