Documentation: Network Monitoring

The following is a guide to monitoring network interfaces and the network from the Solaris operating system.
Note: This document is not written by Sun.
Brendan Gregg, 09-Oct-2005, version 0.70.


Is your network busy?

The network often gets blamed when things are performing poorly, and perhaps this is correct - your network interfaces may be running at 100% utilisation.

What command will tell you how busy the network interface is? Many sysadmins suggest using netstat -i to find out,

This shows packet counts per second, the first line is the summary since boot. How many packets would mean the interface is busy? 100/sec, 1000/sec?

What we do know is the speed of the network interface, for this one it is 100 Mb/sec. However we have no way of telling the size of the packets - they may be 56 byte packets or 1500 bytes. This means that the packet count is not useful, perhaps it is useful as a yardstick of activity only. What we really need is Kb/sec...


Contents


By System

How to monitor network usage for the entire system, usually by network interface.


Across Network

Analysing the performance of the external network.


By Process

How to monitor network usage by process. Recently the addition of DTrace to Solaris 10 has allowed the creation of the first network by process tools.


Back to Brendan Gregg's Homepage


Created: 09-Oct-2005
Last updated: 09-Oct-2005
Copyright (c) 2005 Brendan Gregg