UNIX® Fault Management: A Guide for System Administration

Identifying Important Disk Monitoring Categories

As already mentioned, redundancy is the best way to protect against initial failures. The key to high availability is to always maintain redundancy so that a disk fault does not adversely affect system and data availability. Sometimes, however, this isn't enough. If the resources aren't performing normally, availability can be affected by degraded performance, too.

Regardless of whether you have your disks configured for high availability, monitoring can help protect against failures. Although redundancy helps to provide protection from an initial hardware failure, monitoring needs to be done to protect not only against a second failure, but also against other failures that may affect availability. ...