Linux/Memory

* Turning off yum-updatesd, saved me 50M of memory. Turn it back on if you need it with /etc/init.d/yum-updatesd start. WTF is this used for anyway?

* To turn off X11 in /etc/inittab:
id:3:initdefault:
To turn on X11, change 3 to 5 in that line.
Turning off X11 saved me > 200MB!

* Other random processes to turn off:
autofs,sendmail

* See your biggest resident memory hogs in reverse sort (in KB):
ps -eo pid,ppid,rss,vsize,pcpu,pmem,cmd -ww --sort=-rss

* Your biggest CPU hogs in reverse sort:
ps -eo pid,ppid,rss,vsize,pcpu,pmem,cmd -ww --sort=-pcpu

* Why free(1) memory doesn't go down even though ps and vmstat say it did:
http://sourcefrog.net/weblog/software/linux-kernel/free-mem.html