> i am always wondering why people run clusters with number of nodes == rf > > i thought you needed to have number of nodes > rf ti gave any sensible > behaviour... but i am no expert at all
No. The only requirement is that the number of nodes be >= RF, since clearly in a cluster with fewer nodes than RF you cannot satisfy RF. You select your RF for purposes of redundancy and the consistency level you wish to achieve, in combination with availability. Scaling the cluster to sizes beyond RF is something you do for performance. They're not tied, other than the "cluster size >= RF" restriction. (I'm not being *entirely* correct; there are cases where a higher RF makes sense for performance but I'd say they're sufficiently obscure/specifc that that if you're in that position you hopefully know it anyway.) -- / Peter Schuller (@scode on twitter)
