Right, makes sense and experimenting with different systems is the only sane way to make a solid idea about the different solutions... instead of asking on twit

Right, makes sense and experimenting with different systems is the only sane way to make a solid idea about the different solutions... instead of asking on twitter what NoSQL database to use ;) Btw it's worth noting that there are on-disk databases that will behave pathologically in scenarios where the available memory starts to get seriously smaller than dataset. For instance I saw instances of MySQL that once the data set size reached a given threshold the performance started degradating exponentially. This can probably be avoided.