I have been running into a problem with Virtualmin now for quite some time. I host about 8 different domains, and about half of them use mysql databases for wordpress or mediawiki.
I find that if I let the server run without rebooting, eventually after about a week, users start getting "error establishing a database connection", and either Apace or mysqld have to be restarted. I also notice that on my system, which has 1.5GB of memory, that only 700MB are used, but over time, the amount of swap space grows to 100-200MB. Resetting mysqld and apache clear out most of the swap.
Does anyone else observe this behavior with Virtualmin? Do I have a memory leak somewhere? I'm trying to troubleshoot this issue. I've tried several different servers on different providers, and even Ubuntu and CentOS distros, but I'm getting the same problem. The sites get maybe 200-300 hits total for a day, not high volume at all.