Have you ever considered your servers performance?
Perhaps you don’t need it, because memories and disks are not so expensive and your servers have enough of them.
In my case, one of mine is little bit poor about memories. So I have made some turning to programs such as httpd cut modules which is not needed currently. Even though they are already minimized, free memories are slowly decreased little by little. This is caused by squid and memories should be needed to be free periodically.
# echo 0 > /proc/sys/vm/drop_caches
# echo 1 > /proc/sys/vm/drop_caches
# echo 2 > /proc/sys/vm/drop_caches
# echo 3 > /proc/sys/vm/drop_caches
You could make script with those above and done by cron. If you have interest and want to know more, try below link.
http://www.atmarkit.co.jp/flinux/rensai/tantei01/bangai01c.html