Does anybody has any idea on Fault Tolerance for Schedule Scripts?

@battk thanks

keep in mind that this failed badly enough that is was not implemented in suitescript 2

I tend to try and arrange scheduled scripts to somehow flag when they have completed a cycle successfully

We built an engine (called QueueManager) which is designed for just such a purpose -- to ensure that work that should be done in the background gets done, with audit trails, retry capability, etc. If you are interested, send me an email and I can explain more.