constant mysql connection issues?

You would get better idea from MySQL logs

/var/log/myslqd.log

 

Most forum software can report the exact error being given, but you might be hitting your mySQL max connections. Check your /etc/my.cnf for low values on:

Code:

max_user_connections=25
max_connections=300

Very active forums can use a lot of connection slots under high concurrent usage. Raising those values and restarting mySQL is a good thing to try out. Don't raise them too high as those limits are in place for a reason. Setting them too high can run you out of server resources very quickly. Without knowing the exact error this is no more than a guess at the cause of the issue, but it might point you in the right direction.

 

This is most likely due to the script not closing connections to mysql properly or is getting too busy at times. There is a 25 (max_user_connections) concurrent mysql connection limit which is good for around 100 simultaneous visits on well written scripts. If a script is keeping connections open then obviously 25 concurrent connections do not go far and some of your visitors would see an error.

 

Install munin and mysql plugin to monitor the mysql server and get stats out of it. Then try to make a decision from the graphs. You can also try tunning-primer.sh to get draft idea about your mysql system variables setting .. hope that helps