(I may comment on other things more later) > As a side note: vnodes fail to provide solutions to node-based limitations > that seem to me to cause a substantial portion of operational issues such > as impact of node restarts / upgrades, GC and compaction induced latency. I
Actually, it does. At least assumign DF > RF (as in the original proposal, and mine). The impact of a node suffering from a performance degradation is mitigated because the effects are spread out over DF-1 (N-1 in the original post) nodes instead of just RF nodes. > think some progress could be made here by allowing a "pack" of independent > Cassandra nodes to be ran on a single host; somewhat (but nowhere near > entirely) similar to a pre-fork model used by some UNIX-based servers. I have pretty significant knee-jerk negative reactions to that idea to be honest, even if the pack is limited to a handful of instances. In order for vnodes to be useful with random placement, we'd need much more than a handful of vnodes per node (cassandra instances in a "pack" in that model). -- / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
