Best stress test is when you max out the players skills for a SHORT time (normally a day or two tops) and everyone meets at one town, then they all emote (the animated kind) hunt in the same area (kinda hard to do when there aren\'t half enough monsters...but we could try), and cast like maniacs... I know...not very RP, but testing isn\'t always RP, sometimes you have to dispell the illusion...or the game dispells it for you. (fly glitch, npcs that don\'t know what you are saying etc).
I remember counting server crashes in several beta I was in. I think in Horizons we got to 25 or was it 30.
In Ryzom...they recovered and tweeked it enough rather quickly. I think we MIGHT have gotten to ten crashes. The last one we had to really TRY to crash it, I think it crashed when we got ten extra Trykers all in one spot (their graphics were buggy in beta) and they all cast at the same time, plus all the other races casting emoting etc.