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From DuyHai Doan <doanduy...@gmail.com>
Subject Re: Load balancing issue with virtual nodes
Date Thu, 24 Apr 2014 21:00:33 GMT
I did some experiments.

 Let's say we have node1 and node2

First, I configured Hector with node1 & node2 as hosts and I saw that only
node1 has high CPU load

To eliminate the "client connection" issue, I re-test with only node2
provided as host for Hector. Same pattern. CPU load is above 50% on node1
and below 10% on node2.

It means that node2 is playing as coordinator and forward many write/read
request to node1

 Why did I look at CPU load and not iostat & al ?

 Because I have a very intensive write work load with read-only-once
pattern. I've read here (
http://www.datastax.com/docs/0.8/cluster_architecture/cluster_planning)
that heavy write in C* is more CPU bound but maybe the info may be outdated
and no longer true

 Regards

 Duy Hai DOAN


On Thu, Apr 24, 2014 at 10:00 PM, Michael Shuler <michael@pbandjelly.org>wrote:

> On 04/24/2014 10:29 AM, DuyHai Doan wrote:
>
>>   Client used = Hector 1.1-4
>>   Default Load Balancing connection policy
>>   Both nodes addresses are provided to Hector so according to its
>> connection policy, the client should switch alternatively between both
>> nodes
>>
>
> OK, so is only one connection being established to one node for one bulk
> write operation? Or are multiple connections being made to both nodes and
> writes performed on both?
>
> --
> Michael
>

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