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From Alexander Shorin <kxe...@gmail.com>
Subject Re: Couchdb benchmark shows weird behaviour
Date Wed, 09 Apr 2014 16:36:30 GMT
On Wed, Apr 9, 2014 at 7:11 PM, Arnaud Schoonjans
<arnaud.schoonjans@student.kuleuven.be> wrote:
> The purpose of the firewall rule in the middle of the benchmark is to
> simulate network-failure. The benchmark test examines how the couchdb
> database reacts to a network partition by looking at the latency of the
> different operations in time.

Side note: if you really want to test behavior on unstable networks, use netem
http://www.linuxfoundation.org/collaborate/workgroups/networking/netem
Since destination down is quite trivial case and you only can test
there timeouts and request repeating. Packets loss, corruption and
duplication, rate limiting and delays are the real behavior of the
real unstable networks, especially like wifi and 3g.

About the subj: what have you used for balancing? Are you sure that
this phenomena isn't balancer issue which tries to reach "failed" node
before try the next one - that could cause the latency.

As usual for any benchmarks, it would be good to see numbers and
how-to guide to reproduce test bench and results locally.

Thanks.

--
,,,^..^,,,

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