The led in the pi indicated that it was running well.
If the green led just comes on and stays on, it isn't booting at all. It will probably do the same thing with no card in -- try it. Although I think the 3(+)'s I have do the opposite (light never comes on for no SD card), I do no know whether this depends on model number or something else.
Normally, the green led indicates the SD card is being accessed. So it will flash rapidly and irratically at boot, and thereafter reflect the state of the system. Unless you are using it as a busy database or file server, once relevant stuff is loaded into memory, that activity should die down.
A wiki does potentially make a lot of regular database access depending on how big it is and how active users are. But if it cannot be reached online, it probably should fall into inactive after not very long. If instead it is flickering endlessly, it may be stuck in some issue at boot.
You should have a look at the root filesystem logs in another computer and see if there are any clues about what is happening there. Note that if the green LED is flashing in a very regular, repeated pattern, this means something else again. However, that is pretty obvious.
