You should NEVER have a "down for maintenance" page showing

As I look now, the entire site is "down for maintenance". Of course this will happen from time to time; any amateur web administrator knows it. But any commercial venture with a clue would have an admin on staff who would point out the need for a static backup or failover mirror.

Scrimping on administrative staff expertise is, as I've said elsewhere, like an old-fashioned actual newspaper scrimping on printing expertise. Foolish.