Partioning and Replication Factor.

[Paolo Forte]

Hi,

I have a doubt on a configuration I am using for some experiments.

Basically, I issue write and read requests from a client machine using the built-in performance tool.

I have 2 nodes running on different machines with replication factor 2 (see attached config files). The partitioning is the following: 

Node 0 =  partitions 0,1

Node 1 =  partition 2,3

My goal is is to retrieve/insert as fast as possible the data. I thought to use a full replication setting in order to retrieve/insert each value from/to both the nodes and collect the fastest response. example: the client wants to read or write X. It sends 2 requests, one towards Node 0, the other towards Node 1. Eventually it will collect the fastest response, ignoring or resetting the remaining connection of the slowest response.

Am I wrong or with this configuration I won't achieve replication factor 2? I mean, it can happen that the datum X is only on one of the two nodes. So I guess that the configuration I need is the following, right?

Node 0 =  partitions 0,3

Node 1 =  partition 1,3

Moreover, what is the difference between having 4 partitions instead of just 2? ( e.g. Node 0 = partition 0, Node 1 = partition 1 ) 

Last check, is this the right way to be capable to issue requests towards both the nodes at the same time? I assumed the client is informed of the address of the 2nd node and automatically issue requests toward both of them

./voldemort-performance-tool.sh <...> --url tcp://192.168.0.9:6666 --store-name test

Thanks!

store configuration file

<store>

  <name>test</name>

  <persistence>bdb</persistence>

  <description>Test store</description>

  <owners>ha...@hogwarts.edu, herm...@hogwarts.edu</owners>

  <routing-strategy>consistent-routing</routing-strategy>

  <routing>client</routing>

  <replication-factor>2</replication-factor>

  <required-reads>1</required-reads>

  <required-writes>1</required-writes>

  <key-serializer>

    <type>string</type>

  </key-serializer>

  <value-serializer>

    <type>string</type>

  </value-serializer>

  <hinted-handoff-strategy>consistent-handoff</hinted-handoff-strategy>

</store>

cluster.xml

<cluster>

        <name>myprodcluster</name>

        <server>

                <id>0</id>

                <host>192.168.0.9</host>

                <http-port>8081</http-port>

                <socket-port>6666</socket-port>

                <admin-port>7777</admin-port>

                <partitions>0, 1</partitions>

        </server>

<server>

      <id>1</id>

      <host>192.168.0.7</host>

      <http-port>8081</http-port>

    <socket-port>6666</socket-port>

      <admin-port>6667</admin-port>

      <partitions>2, 3</partitions>

    </server>

</cluster>