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From Bongseo Jang <grayce...@gmail.com>
Subject Re: What is 'Read Reuqests' on OpsCenter exaclty?
Date Fri, 24 Apr 2015 00:35:11 GMT
Thanks a lot Carlos, Sebastian :-)

My test was with 1 node/1 replica settings, on which I assumed client
request = read request on the graph. Because there seems no read_repair and
already CL=ONE in my case, I need more explanation, don't I? Or can any
other internals be still involved?

Do you have more suggestions? I want to design new test narrowing the gap
on the suggestions.

On 24 April 2015 at 00:23, Sebastian Estevez <sebastian.estevez@datastax.com
> wrote:

> Carlos is right:
>
> *Read Requests* - The number of read requests per second on the
> coordinator nodes, analogous to client reads. Monitoring the number of
> requests over a given time period reveals system read workload and usage
> patterns.
>
> *Avg* - The average of values recorded during a time interval.
>
> A future version of OpsC will include tooltips with these descriptions for
> better clarity.
> On Apr 23, 2015 6:30 AM, "Carlos Rolo" <rolo@pythian.com> wrote:
>
>> Probably it takes in account the read repair, plus a read that have
>> consistency != 1 will produce reads on other machines (which are taken in
>> account). I don't know the internals of opscenter but I would assume that
>> this is the case.
>>
>> If you want to test it further, disable read_repair, and make all your
>> reads with CL=ONE. Then your client and Opscenter should match.
>>
>> PS: Speculative_retry could also send reads over to more machines.
>>
>> Regards,
>>
>> Carlos Juzarte Rolo
>> Cassandra Consultant
>>
>> Pythian - Love your data
>>
>> rolo@pythian | Twitter: cjrolo | Linkedin: *linkedin.com/in/carlosjuzarterolo
>> <http://linkedin.com/in/carlosjuzarterolo>*
>> Mobile: +31 6 159 61 814 | Tel: +1 613 565 8696 x1649
>> www.pythian.com
>>
>> On Thu, Apr 23, 2015 at 10:34 AM, Bongseo Jang <graycells@gmail.com>
>> wrote:
>>
>>> I have cassandra 2.1 + OpsCenter 5.1.1 and test them.
>>>
>>> When I monitored with opscenter 'read requests' graph, it seems the
>>> number on the graph is not what I expected, the number of client requests
>>> or responses.
>>>
>>> I recorded actual number of client request and compare it with graph,
>>> then found they're different. The number on the graph is about 4 times
>>> larger than what the client claimed.
>>>
>>> So, my question is what 'Read Reuqests' on OpsCenter counts exaclty ?
>>>
>>> Thanks !
>>>
>>> --
>>> Regards,
>>> Jang.
>>>
>>>  a sound mind in a sound body
>>>
>>
>>
>> --
>>
>>
>>
>>


-- 
Regards,
Jang.

 a sound mind in a sound body

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