September 2004
Intermediate to advanced
192 pages
10h 12m
English
Content preview from sendmail 8.13 CompanionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 6. Tune Performance
When sendmail is installed with near-default
settings, it provides excellent email services for most machines. But
when installed to service high loads, high volumes, or high rates,
special tuning becomes a requirement.
What’s New with V8.13
There are a few new items in V8.13 that affect performance tuning. They are described in other chapters but referenced here. In this chapter, we augment some of the knowledge imparted in the third edition of the sendmail book.
The
RequiresDirfsyncoption (Section 24.1.12 [V8.13]) turns off theREQUIRES_DIR_FSYNC(3.4.47[3ed]) compile-time macro’s setting at runtime. Turning off directoryfsyncsincreases performance—but at (possibly) increased risk.The existing
SuperSafeoption (24.9.107[3ed]) now accepts a newPostMiltersetting that delaysfsync( )ing thedffile until after all Milters have reviewed the message. This improves performance when a great deal of email is rejected by Milters that review the message body.The
Timeout.queuereturn.dsn(Section 24.1.15[V8.13]) andTimeout.queuewarn.dsn(Section 24.1.16 [V8.13]) options have been added. Use them to lower bounce timeouts, and thereby to create less congested queues and increase performance.Some sites have developed delivery agents that receive messages using SMTP over standard input/output. Such delivery agents use the
P=[LPC]equate (20.5.11[3ed]) to achieve this effect. Beginning with V8.13,sendmailenables connection caching (24.7.5[3ed]) for such ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.