Tuning the network

In this recipe, we will look at tuning the network for better performance. This recipe is very much limited to the operating system parameters and not the optimization of routers or switches.

Getting ready

To step through the recipe in this section, we need at least one node to test and to make the configuration changes, and the same can be applied to all the nodes in the cluster.

How to do it...

1. Connect to a node which at a later stage will be used to install Hadoop. We are using the node master1.cyrus.com.

2. Switch as user root or have sudo privileges.

3. Edit the /etc/sysctl.conf file to tune parameters which affect the network performance. The parameters shown in the next steps need to be changed in this file.

4. Change the port range by adding the following line:

   net.ipv4.ip_local_port_range = 1024 65535

5. Enable TCP socket reuse and recycle by using the following line:

   net.ipv4.tcp_tw_recycle = 1
   net.ipv4.tcp_tw_reuse = 1

6. Tune the SYN backlog queue by adjusting the following values....