We've been talking to our service provider about ways of increasing the stability of the server, and they're of the opinion that given that we have over 1.2m posts and a database that exceeds 2gb (which I get the impression is a bit big), we should really have more RAM on our server to give it some breathing room when it gets busy. We typically have in the region 400+ people browsing the forum at any one time during the daylight hours, and we shift some sizeable chunks of data around. The last time I looked at the stats (also the first time!) we have an average of over 8 million page impressions each month, with almost 46 million hits from 675,000 visits. That's a lot, and it takes its toll on our server.
We're currently looking into installing extra memory and are waiting for quotes from our hosts before proceeding. The server will need to be powered off to install the RAM once we've decided how much to put in (as much as we can afford), but we'll post up a warning, and try to make it happen during the European night, where the largest percentage of our membership resides. It should be pretty quick to do once the technician gets to our box in the datacentre, as it's just a case of opening the box, taking out the old RAM (if necessary) and slotting in the new DIMM(s), then closing up the box and pushing the power switch. They may run some diagnostics on the new configuration in order to check it works, but we shouldn't be down too long unless there's a problem.