Consider ketama option as well for CH

[SEJeff]

Ketama is an alternative to cityhash which is designed to limit the amount of rebalancing when new servers are added / removed from a CH ring.

[vmg]

Hi @SEJeff! Thanks for the pointer! Because of the way Graphite works, the aggregator is never in charge of selecting the way metrics are sharded. Best Practice (TM)(C) when running a graphite cluster is reporting metrics evenly distributed to a set of Carbon Relays. The carbon relays already use consistent hashing because that's part of Graphite's design, so the job of the aggregator is to simply spread out the load evenly -- something which CityHash does really well and much faster than any CH scheme.

Hope that clears it up!