I’ve recently discovered, that anyone planning to run simple FreeBSD server for some standalone Internet domain (mail+AV+SpamAssassin, DNS, Apache+MySQL+PHP+WordPress) need at least 512 MB RAM (this server runs this, and some minor addons, and chocks with its 256 MB of RAM). I know that is small amount per today’s standards, but when You use as Your servers :) cheap, used comodity PCs, as I do, You ran on some restrictions. This is some ancient IBM PIII workstation and it has limited memory support – maximum amount is 512 MB… So after upgrade, next memory shortage means only buying new box.
But as upside of this situation is dmidecode utility. I did not know it earlier. It is very handy tool to read information provided by SMBIOS/DMI standards. This means You can remotely check how many memory banks PC has, how they are filled and how much memory You can stuff in motherboard (and many other information). dmidecode have saved me a lot troubles with checking what I can do to upgrade this server. It has special value, when manufactures specifications are not available. I must say, that for many older PCs IBM, HP and others are not providing manuals on theirs webpages… Let’s live dmidecode…
UPDATE
I mean – running on FreeBSD 6.x series. I have really ancient 4.11 box ;-) and there resource consumption is somehow smaller, like perl 5.8.8 from amavisd-new on 6.x series 50 MB, 33MB on 4.11 – values are taken from RES field from top. Maybe it has something to do with RES calculation, but 4.11 box with similar services is much more responsive, than 6.x box with stronger CPU and equal amount of RAM.