Storage that was paid for but never claimed

When a pair of drives in one server was replaced with larger ones, the array was rebuilt correctly but never told to use the extra space. The result was a server running at roughly half the storage it was supposed to have, for weeks.

Nothing reported this, and that is the part worth noting: the storage controller reports an array as healthy whether or not the space on it has been claimed. There was no error to find. The capacity has now been claimed and the usable pool has roughly tripled.