The most common monitoring task is monitoring for full filesystems. On different flavors of UNIX the monitoring techniques are the same, but the commands and fields in the output vary slightly. This difference is due to the fact that command syntax and the output columns vary depending on the UNIX system.
We are going to step through the entire process of building a script to monitor filesystem usage and show the philosophy behind the techniques used. In scripting this solution we will cover six monitoring techniques, starting with the most basic monitoring — percentage of space used in each filesystem.
The next part will build on this original base code and add exceptions capability allowing an override of the script's set threshold for a filesystem to be considered full. The third part will deal with large filesystems, which are typically considered to be a filesystems larger than 2 gigabytes, 2 GB. This script modification will use the megabytes (MB)-of-free-space technique.
The fourth part will add exception capability to the MB-of-free-space method. The fifth part in this series combines both the percentage-of-used-space and MB-of-free–space techniques with an added auto-detect feature to decide how to monitor each filesystem. Regular filesystems will be monitored with percent used and large filesystems as MB of free space, and, of course, with the exception capability. The sixth and final script will allow the filesystem monitoring script ...