Rule-based performance analysis of storage appliances

A rule-based performance analysis tool and a method analyze metrics from a network storage system and generate recommendations for resolving actual or anticipated performance problems. The tool and method collect system metrics from one or more sources, including a storage appliance and optional user-reported comments and/or information about proposed changes to the network storage system. A rule base is applied against the collected metrics and user inputs. Each rule is associated with one or more metrics and has one or more threshold values. A rule can analyze a rate of change of a metric. For each triggered rule, the tool provides an output that includes an explanation of the rule, a suggested action to alleviate or avoid the problem that triggered the rule and, optionally, a priority level. The outputs are presented in a hierarchical display.