I'm a big fan of Varnish. It makes HTTP redundancy a lot easier, even for small networks like mine.
I've previously felt that 256MB or more RAM was necessary, but I'm experimenting with a setup now that seems to work.
Here's my setup:
Here's the /etc/sysconfig/varnish file I'm using:
DAEMON_OPTS="-a localhost:6081 \ -T localhost:6082 \ -f /etc/varnish/default.vcl \ -w 1,4,10 \ -p sess_timeout=2 \ -p thread_pools=3 \ -p first_byte_timeout=300 \ -u varnish -g varnish \ -s file,/var/lib/varnish/varnish_storage.bin,1G"
I'm running this on an OpenVZ container. Seems to work OK.
# free -m total used free shared buffers cached Mem: 128 116 11 0 0 0 -/+ buffers/cache: 116 11 Swap: 0 0 0
UPDATE: Today, about two days after I originally wrote this post, I tried to ssh into this machine and was greeted with an ssh error. I think it was starving for memory. I was able to reboot it, but I guess its just not happening.