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This chapter describes the tools and facilities Unix offers for monitoring and managing the system's CPU, memory, disk and network resources, including some of the limitations inherent in the Unix approach. The first part of the chapter provides an overview of system performance considerations and then discusses Unix processes. The chapter then goes on to consider managing the various sytem resources—CPU, memory, local and network I/O, disk space—in detail.
A large part of managing any system resource is knowing how to measure and interpret its current state, and so we'll spend some time looking at ways to monitor resources and to track their use over time.