On 14.5.2013 16:58, Wietse Venema wrote:
With 100 delivery agents, this means you can have 80 slow messages
in the active queue, right?
Not exactly.
It means that
- with 100 delivery agents, only up to 80 can be tied by the slow mail,
and 20 always remain dedicated to the "fast" mail,
and also that
- with active queue size of 10000, only up to 8000 of those can be from
the deferred queue, and 2000 are always dedicated to the incoming queue.
The same principle is applied to both bottlenecks. That should be enough
for qmgr to keep the mail flowing.
If I decide I need more delivery agents dedicated for the new mail, I
have the option of either decreasing the ratio limit (even as little as
50% is still fair), or increase the total number of clients. The major
advantage here is that if I double the total number of clients, I am
guaranteed to get twice as much for the fast mail.
In comparison, without this ratio limit knob available, if I were to
follow Viktor's advice of bumping the transport limit through the roof,
I would need to set the limit to 1220 to get the same 20 delivery agents
available for the fast mail, as 1200 would be blocked by the slow mail
(assuming 60:1 split, e.g., 30sec vs 0.5sec delivery times, as an example).
Patrik
