> It should decrease peak load of cyrus generated by sendmail deliveries.
The cyrus backend server has a few thousand mailboxes, and four frontents are sending quite a lot of mails but the load on the backend is really low. > Have you considered making sendmail "chain" deliveries to cyrus via LMTP ? > * multiple messages over single LMTP connection > * a small delay before delivery (<30s for most messages) Bypassing the problem by openning fewer lmtp connection is your idea. Actually the mta's execute custom filters per recipient, using mimedefang and stream_by_recipient feature, so each message generates a new lmtp connection. I think there is no way to optimize that in these conditions no ? > [make cyrusv2 "expensive", make it use a separate queue group, use persistent > queue runners, use MinQueueAge (delay *between* delivery attempts] The idea is to requeue messages to be delivered to cyrus in a separate queue, in order to group the delivery via lmtp ??? It is more an mta problem (off-topic here) but I don't know if/how I could tell sendmail to send multiple differents mails over one lmtp connection... Thanks Greg