I guess it depends how you define 'full' fault tolerance. In the case of a machine failure it would lose a couple of seconds worth of transactions. In a data-pr

I guess it depends how you define 'full' fault tolerance. In the case of a machine failure it would lose a couple of seconds worth of transactions. In a data-processing scenario thats not an issue - just re-run the data that hasn't been processed yet. In an exchange the recovery delay is a bit more painful and there is always the potential to permanently lose transactions. Unfortunately there doesn't seem to be a way around that - we must have consistency and performance so machine failure is always going to cause some interruption to availability