[Tony]

Originally Posted by mistwang

If you got some spare memory in your server not being actively used, there is one tip to improve PHP and overall server performance.

Requirements:

* there are enough free memory to spare.
* /dev/shm/ should be mounted as tmpfs.

Install eaccelerator with PHP suEXEC, set disk cache storage to /dev/shm/eaccelerator/ instead of /tmp/eaccelerator/, then add a cron job to clean the cache directory every 5-10 minutes, so cache files not being used frequently will not fill up the precious shared memory storage.

Noticed that the server load going down from 4.x to 1.x on one client's server.

Interesting.

We played around with eaccelerator a bit on one machine but for the density of our machines it's not even worth doing. We actually had higher i/o wait due to the amount of cached files it ended up writing. I think in the end we had about 12GB of cached files eccelerator does have a memory only feature but I did not see any real improvements. I'm guessing it has to do with the timeout of the PHP processes and such.

This /dev/shm idea seems interesting though. I might play around with that when we start deploying nehalem based servers with 12+GB of ram.