I think I’ve found the culprit as the site seems a lot healthier now. I’ve disabled the Reader Posts plugin, which was showing what posts were just read by other users. I think what was happening was that because of the high load my site was under, the list of posts generated by Readers Posts was constantly changing which meant that my APC/WP-Cache2 caching combo wasn’t working as every page load was unique.
Pity, as I really liked that plugin but I guess I don’t need it now that I have some kick-ass WordPress stats with Mint.
I’ve made the PowerVPS server upgrade permanent. I was supposed to be doing something really important tonight, but instead I’ve wasted 3 hours trying to get my site running. I’d rather pay the extra cash for peace of mind, rather than panicking everytime my site gets more traffic than usual. Also, the exchange rate is pretty good at the moment so my pounds go a long way!
I don’t know if PowerVPS are the cheapest but their response times are amazing and they are always very helpful, so I’m happy to pay a premium for good service and piece of mind. If you’re looking for a new host I’d definitely recommend PowerVPS.
