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From Peter Schuller <peter.schul...@infidyne.com>
Subject Re: Will writes with < ALL consistency eventually propagate?
Date Tue, 08 Nov 2011 03:05:41 GMT
> Given that, the way I've understood this discussion so far is I would have a
> RF of N (my total node count) but my Consistency Level with all my writes
> will *likely* be QUORUM -- I think that is a good/safe default for me to use
> as writes aren't the scenario I need to optimize for latency; that being
> said, I also don't want to wait for a ConsistencyLevel of ALL to complete
> before my code continues though.
> Would you agree with this assessment or am I missing the boat on something?

Are you *sure* you care about latency to the degree that data being
non-local actually matters to your application?

Normally you don't set RF=N unless you have particularly special
requirements. The extra latency implied by another network round-trip
is certainly greater than zero, but in many practical situations
outliers and the behavior in case of e.g. node problems is much more
important than an extra millisecond or two on the average request.
Setting RF=N causes a larger data set on each node, in addition to
causing more nodes to be involved in every request. Consider whether
it's a better use of resources to set RF to e.g. 3 instead, and let
the ring grow independently. That is what one normally does.

-- 
/ Peter Schuller (@scode, http://worldmodscode.wordpress.com)

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