Sometimes little oddities like this make me curious! The question is when your indexes are in backup mode (ie read-only) and you issue a request to rebuild an index, what happens?
Firstly the request is queued, as is mentioned in the dialog when you start the rebuild:
This is also logged in the event log:
Then sometime later when the index comes out of backup mode the rebuild will start. It won’t start straight away. The index server needs to be ‘activated’, perhaps by the end-user trying to do a search, or I believe the index server checks hourly for tasks to perform.
By the way, if a user does try to do a search, they’ll see:
When the rebuild is completed, the event log will get the normal message added to it saying that the rebuild was complete.
Note: This is pre-EV10