On Sat, Aug 31, 2013 at 01:03:34PM +0530, Sachin Shetty wrote: > Thanks Willy. > > I am precisely using it for caching. I need requests to go to the same > nodes for cache hits, but when the node is already swamped I would prefer > a cache miss over a 503.
Then you should already be using "hash-type consistent", otherwise when you lose or add a server, you redistribute everything and will end up with only about 1/#cache at the same place and all the rest with misses. Not many cache architectures resist to this, really. Interestingly, a long time ago I wanted to have some outgoing rules (they're on the diagram in the doc directory). The idea was to be able to apply some processing *after* the LB algorithm was called. Such processing could include detecting the selected server's queue size or any such thing and decide to force to use another server. But in practice it doesn't play well with the current sequencing so it was never done. It could have been useful in such a situation I think. I'll wait a bit for others to step up about the idea of redistributing connections only for consistent hashing. I really don't want to break existing setups (eventhough I think in this case it should be OK). Willy
