4.6 I run a mass e-mail to some 40,000 customers every month. My file system gets hammered about 4 times during the mailing at about 10k each. I believe the problem is that mail got so stacked up in the queue, the kernel can't deal with it any longer.

I think you'll run out of file opens before the kernel starts to have serious problems. Regardless, there are some things you can try. Try setting the precedence of the mail to list or less. The allowed precedence settings in sendmail are:


Add a header to your outgoing traffic setting the precedence of the message to list. If you're using majordomo it can be set in the $listname.config file in /var/lib/majordomo/lists/.