Child Process' Question

[Lori]

Hello:

Does anyone know what the default value is for Child Processes?

How would lowering this value to a very small number such as 1 or 2 affect
sendmail with a large amount of inbound mail. Example,...what if the mailer
daemon was seinding a large amount of mail to root how can I stop this and
or minimize how much resources sendmail devotes to procesing this.

Thanks

Lori

[Neil W Rickert]

"Lori" <anon...@newgroup.com> writes:

>Does anyone know what the default value is for Child Processes?

Whatever level causes your system to fail :-(

The sendmail default limit is infinity.

>How would lowering this value to a very small number such as 1 or 2 affect
>sendmail with a large amount of inbound mail.

You would probably lose a lot of mail.

You can work it out.

If you receive (for example) 100 connections per minute, and if it
takes an average of 2 seconds to receive one message, then you will
need 200 process-seconds. Divide that by 60 seconds per minute, and
you will see that you would need more than 3 daemon children to
handle that load. Realistically, you would need more to handle the
burstiness of traffic.

If you allow too few children for the current email rate, some will
get "connection refused". Presumably they will try later. So you
don't have to allow enough processes to handle the heaviest burst.
But you don't want the number so low that a lot of mail arriving in
the morning is refused on every attempt and only makes it at
midnight.

Also, remember that average time to receive a message is not the same
as typical time. A message on a slow connection that takes 10
minutes will tend to push the average way up.

> Example,...what if the mailer
>daemon was seinding a large amount of mail to root how can I stop this and
>or minimize how much resources sendmail devotes to procesing this.

Usually the way to control resources is to use "DeliveryMode=queue",
use frequent queue runs (say, every 5 minutes), and set the
MaxDaemonChildren as high as you can tolerate without exceeding the
resources you wish to allow for sendmail. Make sure that you avoid
going into heavy virtual storage swapping.