Re: [Exim] queue runners not processing mails?

> Is there anyway I can speed this process up without reverting back to
> attempting deliveries as soon as mails are received (which results in >800
> exim processes loading).

I tried queue & queue run as well, and it does introduce ugly latencies.
After all, why should a later queue run be so much more efficient than
immediate delivery with the message probably still in the page cache.

The key to faster delivery is reducing the time messages spend on the
server. Quicker delivery means less simultaneous messages/connections.
You tried to reach less connections by serialising delivery, but that
introduces the additional penalty of possibly losing the cache content.

My strategy is trying to make sure that messages travel through the
system as quick as possibly. If the system is badly overloaded, then
halt delivery at all and only queue to get over the peak, but that's
just borrowing some performance from the future.

Exim does show a weak point here, because it can not do immediate
deliveries until a number of concurrent remote deliveries is reached,
and then keeping exactly that amount of concurrent remote deliveries busy,
like Qmail is able to.

Michael