Yeah.... it's the new year rush.
Every year just after (or about) New Years, we have a major spike in number of visitors. I was hoping to be able to get a server upgrade ready and in place before this year's rush, but just haven't had the time. We've been on this dedicated server for about 2-3 years now, but I think it's time to upgrade to a bigger beefier server. Unfortunately, it means I need to rebuild the system, install all the software all from scratch, and then coordinate the final data migration so all posts get moved over to the new server.
Anyway... we're hitting record numbers for unique visitors per day and page views per day. Right now, one of the biggest constraints is memory on the system. When we upgrade, I expect the new system will have 4 times the memory we currently have and things will seems MUCH more smooth.
But for now, we'll have to suffer. I'm hoping to get some time to work on a server upgrade in the next month or two.
I've updated the error message when the system has to "pause" access to indicate it's due to load.