Book Image

SpamAssassin: A practical guide to integration and configuration

Book Image

SpamAssassin: A practical guide to integration and configuration

Overview of this book

As a busy administrator, you know Spam is a major distraction in todays network. The effects range from inappropriate content arriving in the mailboxes up to contact email addresses placed on a website being deluged with unsolicited mail, causing valid enquiries and sales leads to be lost and wasting employee time. The perception of the problem of spam is as big as the reality. In response to the growing problem of spam, a number of free and commercial applications and services have been developed to help network administrators and email users combat spam. Its up to you to choose and then get the most out of an antispam solution. Free to use, flexible, and effective, SpamAssassin has become the most popular open source antispam application. Its unique combination of power and flexibility make it the right choice. This book will now help you set up and optimize SpamAssassin for your network.
Table of Contents (24 chapters)
SpamAssassin
Credits
About the Author
About the Reviewers
Introduction
Glossary

Bottlenecks


Bottlenecks are the points where data flow is most restricted. In computer systems, the bottleneck may be due to a system resource or a particular process in a chain taking a long time to execute. To determine a bottleneck, some understanding of the resources in a computer system is required.

The main system resources in a modern computer are memory, CPU, and disk and network I/O.

Memory

Memory is a finite resource and is liable to be the scarcest resource for machines running SpamAssassin. Programs running on a machine and the data they process use memory. Memory is often supplemented with swap space or virtual memory. This allows the computer to run more programs or process more data than it might otherwise.

Swapping is not unusual on a machine with many tasks. Some processes sleep when there is no work to be processed, and wake periodically to perform tasks. When these are not processing work, the memory can be used for other tasks and the task is swapped out from the memory...