[svlug] Fw: MICROSOFT ACQUIRES LINUX OPERATING SYSTEM

[George Bonser]

On Sun, 15 Nov 1998, Javilk wrote:

>     That would get rather bad!  Why doesn't sendmail run multiples at
> once?

When sendmail collects a new email, it is normally configured to deliver
immediately. If 10 emails come it, it can fork off 10 processes to deliver
them. If a delivery fails, it is queued. Sendmail will also queue rather
than deliver if the system load is too high. If you send a lot of mail to
a particular domain ... say company headquarters or AOL and that site is
down, the child process that was forked off to deliver it will time out
and the message will be queued. Lets say that over the course of an hour
you have 100 of these. On the next queue run, sendmail will sequentially
process them. If the site is still down, each message will time out ( 5
minutes per message). 100 messages * 5 minutes/message = 500 minutes to
run through the queue one time.

Now some mail servers are configured to queue messages and have the
delivery picked up by a queue runner at regular intervals. If messages are
being processed out of the queue, they are being handled separately.

Going back to the first example ... when handling a large volume of mail,
often the load level goes high enough to force it to queue mail, some
remote sites will defer mail for various reasons etc. Once mail is in the
queue, it can take forever to get out. In other words, if sendmail can not
deliver it immediately, it might be a long time to deliver it.

George Bonser

The Linux "We're never going out of business" sale at an FTP site near you!


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