Patrik Rak:
> We classify every mail into one of the two groups. We can call them fast
> and slow for simplicity, but in fact they are "hopefully fast" or
> "presumably slow". For the start it can be equal to new mail and
> deferred mail, but doesn't have to, as Wietse pointed out before.
>
> Now let's explore what share of the available resources each group gets.
> When both groups contain some mail and the mail is delivered equally
> fast, they get 1:1 split. That seems fair. If the slow group becomes say
> 4 times slower on average, they will get 4:1 split over time. The same
> holds if the fast group becomes 4 times slower, they will get 1:4 split.
> So far, so good.
>
> Now if one group becomes really slow, like 30 or 60 times slower than
> the other one, it's effectively the case when it starts starving the
> other one. If it is the slow group which becomes this slow, it gets
> 60:1 split, which with ~100 delivery agents available is obviously not
> enough to get new mail delivered fast enough. If we were willing to
> increase the transport limit considerably, the 1/61 will eventually
> become enough delivery agents available for fast mail delivery. However,
> what I say is that it's enough if we simply do not allow the ratio go
> this high. We can fairly easily limit the amount of resources we give to
> the bad guys to 80% or 90%, allowing them to get no more than 4:1 or 9:1
> split. That can leave quite enough for the fast group while not wasting
> too much on the bad group. Seems like good trade, especially when we
> presume that most of the bad mail won't get delivered anyway (if it
> were, it wouldn't likely be this slow and demand so much resources in
> the first place).
With 100 delivery agents, this means you can have 80 slow messages
in the active queue, right?
Wietse
