Since your case is special, in that you have only a single destination but many possible origins, I would suggest loading your many origins as Facilities and your single destination as Incidents. Then set your travel direction in the Closest Facility solver to be "travel from facility to incident".
The reason for this suggestion is that the Closest Facility solver always performs a unique search from each incident until either the target number of facilities is found, or until the cutoff is reached. Even in cases where you have specified that the travel direction should be from facility to incident, the search is still done from each incident (for these cases, the solver just searches in the backward travel direction along each edge instead of in the forward direction, thus achieving the desired travel direction).
Therefore, if you load your N origins as incidents and your single destination as a facility (with travel direction = from incident to facility), then this results in N unique searches, one for each of your many origins. If you instead load your single destination as an incident and your N origins as facilities (with travel direction = from facility to incident), then this results in only 1 unique (backward) search from your incident. The resulting output of the final paths are equivalent between these two setups (assuming you are solving for all paths with no limiting target facility count), but since each unique search incurs some additional overhead, it generally pays to go with the approach that results in the fewest number of unique searches.
It�??s a subtle distinction, I know, but it is a crucial one that can significantly impact performance if not properly addressed.
