Linux Settings for High Load Systems

There are a few basic settings you have to adjust for high load systems to make sure the server has enough resources to handle a big number of network connections.

The main parameter is a maximum number of opened files allowed for the process to keep at the same time. Each network connection uses a file handler, therefore if the limit is too low you can quickly run out of handlers and the server can not accept any more connections.

This limit is set on 2 levels - on the kernel level (fs.file-max) and on the system level (nofile).

Another kernel property which can be important in certain configurations (like transports installations or when you use proxy for Bosh connections) is: net.ipv4.ip_local_port_range. This parameter can be set the same way as the fs.file-max property.