Web Caching

Monitoring Tools

Most caching products provide both custom interfaces and monitoring via SNMP (Simple Network Monitoring Protocol). The custom interfaces are typically web-based and often use Java. While these tools can display graphs for some of the parameters just described, they usually have only volatile storage. When the proxy cache restarts, the historical data is lost.

Although most products support SNMP, there is no standard SNMP proxy MIB (Management Information Base). Instead, each vendor or product has its own MIB with product-specific information. If enough customers complain about the lack of a standard MIB, vendors are likely to develop one within the IETF.

In theory, monitoring a network device via SNMP is relatively simple. You make the MIB file available to your network management application and tell it which variables to collect and display. In practice, however, it’s often a frustrating process. There are a number of management applications available for all types of operating systems. As a relatively simple example, the remainder of this section describes how to install and configure UCD-SNMP and RRDTool to monitor a Squid cache. To monitor another SNMP-addressable caching product, you’ll need to use its MIB.

UCD-SNMP

The University of California at Davis distributes a suite of SNMP tools for Unix. You can download the software from their home page, http://ucd-snmp.ucdavis.edu, or one of the mirror sites. Hopefully, you’ll find the software easy to compile and ...