You have got to be kidding me. The machine this server runs on must have a lot of RAM!
Still seems to be a bit fragile, though. I am assuming persistence is a periodic thing, making the system vulnerable to eg. power failure between persist events, ie writing the text files. To be balanced against the simplicity gains of only having to deal with in-program data structures, though, I guess.
Then again it's worked flawlessly for 5+ years so what do I know!