As email traffic continues to increase, system
administrators must be able to guarantee that their email
servers can deliver reliable performance today and bear
larger loads tomorrow. sendmail Performance Tuning is a
practical guide to building, tuning, and testing email
servers based on sendmail to function more efficiently,
handle more messages, and resist both accidental and
malicious load-related incidents.
Featuring sendmail 8.12 (and earlier versions), the book
begins with an introduction to sendmail and performance
tuning. Author Nick Christenson then describes best
practices for building, installing, and maintaining a
system and details proven techniques for tuning email
relaying, reception, and sending. This strategic guide to
configuration and security is followed by precise
directions for managing bottlenecks and load testing. By
the book's end, readers should know exactly how to optimize
system performance.
Key topic coverage includes:
- A detailed description of the step-by-step operations
that occur during email transmission and reception
- How to send and store email most efficiently
- What the performance characteristics of POP and IMAP
are
- How to determine which sendmail configuration
parameters might improve performance
- How to locate and eliminate bottlenecks
- Methods and pitfalls in testing email servers before
they are installed in a production environment
Whether you are looking to solve an immediate problem or
gain a deeper understanding of email servers, sendmail
Performance Tuning provides clear guidance and valuable
insight.
Contents
1. Introduction
- Performance Tuning Examples
- sendmail Versions Covered
- Definitions
- Email Server Tasks
- Tuning Isn't Always Necessary
- Not So Fast
- Email System Profiling
- General Tuning Ideas
2. sendmail Introduction
- Obtaining sendmail
- Building sendmail
- Creating a .cf file
- Why Use M4?
- System Setup
3. Tuning Email Relaying
- What Happens During Relaying
- Synchronization
- File Systems
- File Space
- Networking
4. Tuning Email Reception
- What Happens During Email Reception
- Recipient Verification
- Storage Systems
- Disks
- Solid State Disks
- POP Tuning Specifics
- Message Store Hashing
- IMAP Tuning Specifics
5. Tuning Email Sending
- Mailing Lists
- Command Line Message Generation
- Draining Queues
- Another Mailing List Strategy
- SMTP Pipelining
- More Notes on Mass Mailing
6. Configuration, Security, and Architecture
- Configuration
- Security and Performance
- Other General Strategies
7. Finding and Removing Bottlenecks
- Kernel Parameters Run Amok
- The Quick Fix
- Tools
- syslog
- Removing Bottlenecks
8. Load Generation and Testing
- Test System Setup
- Testing Tools
- Load Testing Pitfalls