> 2. Considers Internet DNS propogation time for finding the new host > IP.
With regard to this particular point, I can say that my experience in doing exactly what you are asking about has shown that there are quite a few ISPs that simply ignore TTLs below some minimum value. For example, when I have done moves as you mention, we always start by cranking TTLs down to 5 minutes, a week before the scheduled move date. At the move time, we turn up the new site, put the old site into "maintenance mode" (showing our standard "please excuse our dust while we do something behind the scenes" screen), then edit the DNS entries to point to the new IPs. In theory, this should ensure no more than 5 minutes of unreachability for anyone, and, no worries about DB replication, because the old site is not accepting any new input. In practice, I have watched in amusement and disgust as requests have continued to appear on the old IPs for a week or more. My guess, although unverified, is that some caching nameservers (probably belonging to ISPs) simply ignore TTLs. If memory serves correctly, it seemed like most of the requests were coming from Asia, so, maybe some ISPs there impose some minimum TTL value to throttle trans-oceanic DNS requests. Don't know for sure, but, that's my experience, on more than one occasion, so, thought I'd throw that out there. Best, Danny -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
