Re: [exim] Performance considerations

Philip Hazel wrote:

> As far as scalability goes, there are ISPs handling millions of messages
> a day with millions of customers, and they do it with Exim. What they
> usually do is implement a multi-level system so that queues on the
> front-line delivery hosts are always short. Fallback hosts are used to
> hold the queues. Multiple levels can be used, e.g. one try on a main
> delivery host, try for 6 hours on the first level fallback, then shunt
> over to another level where the performance may be bad but it doesn't
> matter at that stage.

Yup. The powerpoint that I pointed to in my previous email describes
just such a system.

Using split_spool_directory is also quite useful.