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From David Schoonover <david.schoono...@gmail.com>
Subject Re: Cassandra benchmarking on Rackspace Cloud
Date Mon, 19 Jul 2010 21:45:32 GMT
> Now keep adding clients until it stops making the numbers go up...

Neither adding additional readers nor additional cluster nodes showed performance gains. The
numbers, they do not move.


--
David Schoonover

On Jul 19, 2010, at 5:18 PM, Jonathan Ellis wrote:

> Now keep adding clients until it stops making the numbers go up...
> 
> On Mon, Jul 19, 2010 at 2:51 PM, David Schoonover
> <david.schoonover@gmail.com> wrote:
>> Sorry, mixed signals in my response. I was partially replying to suggestions that
we were limited by the box's NIC or DC's bandwidth (which is gigabit, no dice there). I also
ran the tests with -t50 on multiple tester machines in the cloud with no change in performance;
I've now rerun those tests on dedicated hardware.
>> 
>> 
>>        reads/sec @
>> nodes   one client      two clients
>> 1       53k             73k
>> 2       37k             50k
>> 4       37k             50k
>> 
>> 
>> Notes:
>> - All notes from the previous dataset apply here.
>> - All clients were reading with 50 processes.
>> - Test clients were not co-located with the databases or each other.
>> - All machines are in the same DC.
>> - Servers showed about 20MB/sec in network i/o for the multi-node clusters, which
is well under the max for gigabit.
>> - Latency was about 2.5ms/req.
>> 
>> 
>> At this point, we'd really appreciate it if anyone else could attempt to replicate
our results. Ultimately, our goal is to see an increase in throughput given an increase in
cluster size.
>> 
>> --
>> David Schoonover
>> 
>> On Jul 19, 2010, at 2:25 PM, Stu Hood wrote:
>> 
>>> If you put 25 processes on each of the 2 machines, all you are testing is how
fast 50 processes can hit Cassandra... the point of using more machines is that you can use
more processes.
>>> 
>>> Presumably, for a single machine, there is some limit (K) to the number of processes
that will give you additional gains: above that point, you should use more machines, each
running K processes.
>>> 
>> 
>> 
> 
> 
> 
> -- 
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com


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