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From Daniel Kluesing ...@bluekai.com>
Subject Ring management and load balance
Date Thu, 25 Mar 2010 15:37:13 GMT
I wanted to check my understanding of the load balance operation. Let's say I have 5 nodes,
each of them has been assigned at startup 1/5 of the ring, and the load is equal across them
(say using random partitioner). The load on the cluster gets high, so I add a sixth server.
During bootstrap, the new server will pick the existing server with the highest load, and
take half the load from that server. After boot strap, I would end up with 4 servers with
1/5 of the ring each, and 2 servers with 1/10 of the ring each - is this correct? I'll get
hotspots unless I double the number of nodes?
				
Really I would want adding a sixth server to result in six machines with 1/6 of the load taken
evenly from the existing nodes.  If I understand - and correct me if I'm wrong -, the core
of this is that each server is assigned one token, while in a system like dynamo, a server
is assigned multiple tokens around the ring. Is there any benefit to only assigning one token?
Has anyone worked on assigning a server multiple tokens, or is there some other unrelated
way to get more even load distribution when adding a node?

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