His arguments consistently (hah!) boil down to this: if you misconfigure things for your intended application, you get undesirable behavior. For example, the correct approach to the situation cited is to use quorum reads and writes. W=3/R=1/N=3 might be appropriate for situations in which you want to force writes to a remote datacenter (using appropriate placement strategy), but are not concerned with clients always seeing the same data at any given instant.
b On Thu, Apr 8, 2010 at 12:55 AM, Paul Prescod <p...@ayogo.com> wrote: > In this¹ debate, there seemed to be consensus on the following fact: > > "In Cassandra, say you use N=3, W=3 & R=1. Let’s say you managed to > only write to replicas A & B, but not C. In this case Cassandra will > return an error to the application saying the write failed- which is > acceptable given than W=3. But Cassandra does not cleanup/rollback the > writes that happened to A & B." > > If this is still true (even for ConsistencyLevel.ALL) then I would > like to add it to the API documentation. I'd also be curious about if > there have been discussions about for an optional 2PC mode for use on > fast LANs. > > Paul Prescod > > ¹ http://jsensarma.com/blog/2009/11/dynamo-part-i-a-followup-and-re-rebuttals/ >
