My SMTP server has sending limit up to 5 messages per second. On Drupal 6 site I have up to 500 users in organic groups to whom I would like to send newsletter.
What sending limit should I set for successful broadcast? Does Drupal send messages momentarily or during longer period?
I use Messages & Notifications modules which allow me to limit
- number of messages
- sending time in seconds
- sending time in % of cron time
The only way to solve my problem I've found up to now is limiting the number of messages to 5 and setting cron to run every 15 minutes. But it is very sad to wait whole day to send about 500 messages.