I'm a server admin and upon enabling persistence I've found that items are duplicating after the server crashes or restarts.Upon joining my server I found there was two of each item and when the server restarted there were now four of each item. My server lasted 2 hours then crashed and required a manual restart. After this restart my server only lasted a few minutes and then crashed completely causing me to have to disable persistence in order to get it running again. It would seem that the amount of items on the server is causing the crash.