Working with Graphite 0.9.11 ?

[deniszh]

Hi Mark,

Trying to test your relay against our installation of Graphite 0.9.11 - relay and 4 caches with consistent hashing.
Found everything "working" but graphs on Graphite-web looks totally wrong - like we loosing all caches but one:

Checked that's not true - all 4 caches got updates, and all updates went to disk.
So, my idea was that hashing algorithm in your implementation differs than what Graphite use, and I found that you use just simple CRC32:
https://github.com/markchadwick/graphite-relay/blob/master/src/main/scala/backend/strategy/ConsistentHash.scala#L39-43
but Graphite use int( md5hex() [:4])
https://github.com/graphite-project/carbon/blob/master/lib/carbon/hashing.py#L16-19
https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/hashing.py#L66-69
Could you please tell me if I'm right and providing proper hashing will help? ('cause I'm not very good at scala and I want to spend my time on this patch only if I'm thinking right)

Thanks!

[deniszh]

Tried to mimic Graphite hash - deniszh@6b82ed0 and using hash.replica:100 as in original Graphite - https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/hashing.py#L57
So, hash now produces same result but unfortunately it not helping with issue above... :(

[deniszh]

It seems that problem lies in ways how Graphite and graphite-relay populate rings. Graphite uses something like "(server, instance):replica" as hash key, graphite relay - "server:port-replica", and have no instances at all...
Will try to dig it over weekend.

[deniszh]

I takes more than weekend, but now its working - see #6