Brad Knowles wrote: > At 3:27 PM -0700 2005-05-09, Tyler Strickland wrote: > > >> That's entirely possible - the system is an old sun running sendmail. > > > Older versions of sendmail can certainly have some issues in this > respect. More modern versions work much better, but still require > some additional configuration changes in order to get them to work > better with large mailing lists. > > >> I'm currently building a new mail server to replace it that should be >> able to handle the load much better by running postfix on a >> hyperthreaded Pentium 4. > > > See the stuff in the FAQ about "performance". > > For one, HyperThreading almost always hurts performance and does > not help. This is a seriously dain-bramaged idea that Intel had that > never panned out, although they did get enough people interested in > the concept that once AMD came out with a real dual-core chip, > performance really has improved significantly. > > > For two, you don't need CPU. You need RAM and disk I/O capacity. > Not disk space, but I/O capacity. When an MTA receives a mail > message, it creates one or more temporary files to store that > message. When the message has been delivered, the temporary files > are deleted. Between those two points, there may be many more file > creations, deletions, and renaming operations just for that one > message. > > Each of these types of operations are known as Synchronous > Meta-Data Operations, and they require that the entire directory be > locked against all other changes during the process of that > operation. You would think that this would not hurt performance very > much, but think of a turnstile going into a football stadium -- no > matter how fast it operates, the simple fact that it only allows > through one person at a time will mean that the total throughput is > greatly reduced. > > A fast intelligent hardware RAID array with a large quantity of > battery-backed write-back RAM cache and high-speed internal > interfaces to high-speed drives with intelligent disk queueing (i.e., > SCSI with Tagged Command Queueing, or good SATA drives that actually > properly implement a similar feature) can really help. A fast > filesystem which optimizes synchronous meta-data operations can also > help. > > > But all this is covered in the FAQ, and you should read about it > when you search for "performance". > > I will tell you that if you're trying to build a high-performance > mail/mailing list server, about the worst possible mistake you could > make would be to try to build the machine without first reading the > information on this subject in the FAQ, and reading the various > pieces of documentation that are referenced. > ------------------------------------------------------ Mailman-Users mailing list [email protected] http://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://www.python.org/cgi-bin/faqw-mm.py Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-users/archive%40jab.org
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