In the mainline generic kernel of Ubuntu, there's a module called zram. This is a pretty good trick to add additional "free" RAM to your machine without any change: it creates in-memory compressed block for swap, meaning it eats a bit of your CPU but gives you literally more RAM.
If you're on a VPS for example, having 512 MB RAM, this would actually give you access to 750 MB RAM and would eat just a little CPU from you - I don't even notice it on the Munin graphs.
To install:
apt-get install zram-configMake sure it's started and running:
cat /proc/swapsIf you see something like this
# cat /proc/swaps
Filename Type Size Used Priority
/dev/zram0 partition 62712 6804 5
/dev/zram1 partition 62712 6768 5
/dev/zram2 partition 62712 6744 5
/dev/zram3 partition 62712 6768 5then it's already running.
Reboot your machine, and voilá.
More to read:
(Oh, by the way: this entry was written by Peter Molnar, and originally posted on petermolnar dot net.)
