Adding a new carbon-cache server with consistent-hashing
Say I have 1 server running carbon-relay and 2 servers running carbon-cache; I am using RELAY_METHOD = consistent-hashing to split the metrics between the two carbon cache servers. The carbon-cache servers also run the webapp.
If I then add a third carbon-cache server into the mix it will (I assume) take over roughly one third of the metrics previously handled by the existing two servers.
The problem arises when the webapp queries one of the two original servers for a metric that is now being sent to the new carbon-cache server. When this happens I get a graph that only has data from before when the new carbon-cache server was added. This happens, predictably, two thirds of the time. The other third of the time the webapp will get data from the new server and there will only be data from since the new server was added.
Is there a way to "re-balance" the .wsp files across my servers? What is the suggested method for adding more carbon-cache servers to a consistent-hashing cluster without hitting this problem?
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