The Smartlist on my system used to send list mails in batches of 20 at a time, each batch takes about 2-3 seconds, then next batch immediately follow.
Recently I notice it *sometimes* take a very long "idle" gap between each batch -- about 2-4 minutes, during which the system is not busy, and qmail is not busy:
qmails 2764 1 0 Jan28 ? 00:00:15 qmail-send qmaill 2770 2764 0 Jan28 ? 00:00:08 splogger qmail root 2772 2764 0 Jan28 ? 00:00:01 qmail-lspawn | /var/qmail/bin/preline /usr/bin/procmail qmailr 2773 2764 0 Jan28 ? 00:00:13 qmail-rspawn qmailq 2774 2764 0 Jan28 ? 00:00:01 qmail-clean
This way, a mail used to take under 5 minutes to distribute now takes more than half an hour. I wonder what may cause this behavior change?
Zhiliang