You might like to post your existing /etc/my.cnf file here as well as the results of mysqltuner. You may also like to look at Tuning-primer, which some prefer over mysqltuner: https://launchpad.net/mysql-tuning-primer
That way we can advise on your requirements a little more, rather than the requirements from somebody elses server.
One thing to keep in mind, if you severely limit the memory usage, and your database actually needs it due to the type of queries you have and the way its structured, you will severely hinder the performance.
Posting a config without details of actual usage as per the output of both tuning-primer.sh and mysqltuner.pl is useless as any advice will only be a guess and won't help you at all.
Please, tell us the steps you have taken so far in tuning the config.
Once again, until you run the 2 scripts and post the output you will not get any help.
Mysql has over 300 variables that can be tuned - so unless you are willing to provide requested output nobody will give more of their time to assist you. My suggestion is in fact that you look fir a system admin to do this for you and post a job request for help.
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