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11th Systems Administration Conference (LISA '97)

Tuning Sendmail for Large Mailing Lists

Rob Kolstad
Berkeley Software Design, Inc.


One of BSDI's mail servers hosts what might be the Internet's busiest mailing lists: This list now has about 2,000 subscribers and occasionally processes traffic as high as 200 separate messages per day. This 400,000 message per day aggregate is a taxing load for a non-optimized mailing system.

When the project started, the mail queues sometimes lagged as much as five days (hundreds of thousands of messages) behind. A single message could take more than five hours to attempt delivery to members of the list. Furthermore, the disk load was high as sendmail processed the queues repeatedly (trying to deliver previously missed mail). All in all, the system's efficiency was remarkably low.

This paper describes the procedures undertaken to reduce delivery times to under five minutes (for all 2,000 subscribers) and mitigate problems associated with unavailable hosts.

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Last changed: 12 April 2002 aw
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