Chapter 4. Tuning Email Reception

Besides relaying email by passing it in and out of the mail queue, email servers receive and store messages in the message store for later access by users. Many of the same issues we find in email relaying apply here: The systems are still likely to be file I/O bound, and message deliveries remain synchronous. However, the data moved tend to be less temporary and less transactional. Storage volume requirements are higher, and access mechanisms, such as POP and IMAP, have some different characteristics than SMTP. This chapter discusses these similarities and differences.