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.este...@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" <r...@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 <grayce...@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
