I don't think you need to use anything very scientific. Too high
shouldn't hurt, I don't think memory is allocated needlessly. The
cache timeout value is probably more performance worthwile.
But to calc, I would go with about the number of logins you get per 5
or 10min.
I would think any logins over that period of time would probably be
the same user.
Quoting Frank Bonnet <f.bonnet at esiee.fr>:
> Hello
>
> Is there a way to calculate this parameter for my site
> which has approx 4000 users authenticating thru NIS ?
>
> Thanks a lot
>
>