is UBB one of those scripts that will need to be modified?
Not that I know of. we haven't installed any of the newer versions but last I checked no...
Would it be possible to keep a single server running at the old center during the move with the sole function of redirecting all requests for the 208.243.19.??? IPs to a single default page that contained a short explanation for the unavailability of all these sites?
No, not really. We would have to leave name servers intact to handle every account currently hosted and to redirect visitors to this single page, would only delay their viewing of the new location with your full websites on them not to mention making the task much more complex and adding propagation to the situation.
The shutdown time will actually help by allowing the visitor's cache to timeout without allowing them to recache old entries during the move. When the servers are brought back online with the Tunnels active they will be able to immediately see your websites fully operational as they should be. Going the other way around would cause more of your visitors to be "lost in space" viewing a temp page while others are viewing your site (same affect as transferring a domain name). Using the tunnel system we can make this move virtually painless and not risk losing visitors for days at a time.
The Tunnels will eliminate propagation. As soon as they are brought online visitors will be automagically redirected without anyone noticing. This was tested right here on the forums during prime time and no one seemed to notice the move at all. The reason for the long time frame given for the move is mainly for take down, transfer, and setup time. E.g. we need to physically unplug the servers, pull them down, transfer them to the new location and rehook them back up. In a perfect world anyone who sleeps in the night (EST) and has breakfast before coming online wont even noticed it happened.... for those of us who don't sleep or live on the opposite side of the time clock, yes we'll notice and thus the warning that it may take a while. I'd much rather no one plan on anything until around noon and be early than promise everyone 6 hours or less and have it take 12. What I do know is that if we were to redirect your visitors all over the place the move would end up taking much longer than anyone could accept. I've seen too many "broken NOC moves" and do *not* want to be a part of that.
Redirecting to another server wouldn't really help as they will be trying to get to your current server and during the move it wont be there to redirect them. Transferring the domain name would take longer than the move itself. The best option is really to put a notice up now letting them know you're upgrading and will be back as soon as possible on Sunday morning. For most this is a slow time. I realize *any* time is a bad time, but I do feel the benefits will outweigh the pains...
- We'll apply a local anesthetic for the pain.