Slots
How many players may be on the server at once.
scum.MaxPlayers=64
What does this setting do?
The cap on simultaneous connections, officially between 1 and 128. In practice the sensible figure depends less on this setting than on memory and processing power: every player brings items, vehicles and a base the server has to manage permanently.
On rented servers the figure is tied to your plan. A higher value in the file achieves nothing there — more slots only come from the provider's panel, and usually they cost money.
Too many slots is worse than too few: a full server with poor frame rate drives players away for good, a server with a queue does not.
Which value suits my server?
Size it by your memory, not your ambition.
64 (default) is plenty for most groups.
A smaller figure with dependable performance.
What to watch out for
GPortal and Nitrado set slots through their panel; the value in the file is overwritten or ignored.
A server that runs well with 64 players can struggle months later because bases and vehicles have piled up. Slot count deserves regular review, not a one-time decision.