Consumer throughput and number of partitions

[Arjun]

Hi,

I am trying my hands on kafka 0.8. I have 3 kafka servers and 3 
zookeepers running.With the number of partitions as 10 and replication 
factor of 2, 4 producers were pushing data into kafka, each has their 
own topic. There are 4 consumers which are getting the data from kafka.

The problem i see is with the the number of partitions as 10, consumers 
are not consuming enough messages, the through put is almost all half, 
as supposed to when the number of partitions is 2.

Is this a normal scenario or can we tune this behaviour so that the 
throughput will be high, when the number of partitions are high.

environment 1 :
    kafka servers : 3
    Zookeepers : 3

    producers : 4
    consumers : 4
    topics : 4

    number of partitions: 10
    replication factor : 2

    number of messages pushed to kafka in 10 minutes : 47935 (per 
producer, all producers have pushed almost same number of messages)
    number of messages consumed from kafka in same 10 minutes : 20693 
(per consumer, all consumers have consumed almost same number of messages)

environment 2 :
    kafka servers : 3
    Zookeepers : 3

    producers : 4
    consumers : 4
    topics : 4

    number of partitions: *2*
    replication factor : 2

    number of messages pushed to kafka in 10 minutes : 47935 (per 
producer, all producers have pushed almost same number of messages)
    number of messages consumed from kafka in same 10 minutes : 47720 
(per consumer, all consumers have consumed almost same number of messages)


Thanks
Arjun Narasimha Kota