ah, my flippant comments at the end. Instead of "Single point of failure" perhaps I should have said "specialist nodes are a bad idea as they may reduce the overall availability of the cluster to the availability any one sub group." e.g. a cluster of 10 nodes, where 8 are data and 2 are connections may be down for 100% of the keys after the loss of 2 nodes if they happen to be the connection nodes.
WRT the partitioner I was thinking of a situation such as node 1 : 33.3% of the ring node 2 : 33.3% of the ring node 3 : 33.3% of the ring node 4 : 0.1% of the ring My point was that giving the node a small token range would not be enough to reduce it's data load. If node 4 was a functioning node in the ring then at RF 3 it will be asked to be a replica for the data from nodes 2 and 3. Unless the replica strategy excluded the node from the list of natural endpoints for all but the token range it was responsible for. Aaron On 21 Mar 2011, at 10:28, Robert Coli wrote: > On Sun, Mar 20, 2011 at 1:20 PM, aaron morton <aa...@thelastpickle.com> wrote: >> Even if the node is only >> responsible for a small about of the ring, it would normally still get data >> handed to it and read from it as a replica. You would need to use a Replica >> Placement Strategy that knew it ignore the "connection only" nodes. >> IMHO it's a bad idea: Single point of failure, wasted compute resources, >> imbalance between "connection" and "worker" nodes. > > As I understand what is being proposed, the node could only be > responsible for a single token, and presumably would perform very well > indeed when reading or writing that token. I don't see why you would > need to avoid placing a single token's worth of data on a node, or why > it would become a single point of failure if you did.. is there > something I'm missing.. ? > > =Rob
