Scheduled Server Maintenance Holding Page

Question

we are going to perform scheduled maintenance on our server, which runs IIS etc. We may need to restart the server to update Windows etc. I am wondering if it is possible to configure our DNS records for our domains to direct any connections which cannot be made, to a holding page located on alternate hosting space whilst the server is down. Thanks, Chris

Answer 1

You CAN do this -- simply point the DNS records at an appropriate host -- however this isn't something you want to do via DNS -- You'll be at the mercy of DNS propagation to a nearly infinite number of servers, and you can't tell when they'll get the "holding page" change, or when they'll get the switch back. You will wind up creating a time-scattered outage for what should be a minimum-downtime event if it's planned right.

Your best options in my opinion are:

1. Put up another server (on the usual IP address) to act as a temporary placeholder (with a "currently undergoing scheduled maintenance" page).
   This is friendly to your users, but presumes you have resources (hardware) available to do it.

2. Announce the outage window and do nothing else.
   Anyone visiting your site will get "dead air" (server not responding page from their browser), but if the outage period is short (a couple of hours at most) and during a window few people will be using the site you might be OK.
   This also depends on how understanding your users are...

Answer 2

It's solely dependent on the TTL of the DNS record in question. Set the TTL for the DNS record in question to a reasonable value, say 60 minutes, then 60 minutes or so before you make the change set the TTL to something much lower, say 5 minutes, then when you make the change you'll have at most 5 minutes for the TTL to time out on those hosts that have the record in their DNS cache. For hosts that don't have the record in their DNS cache they'll see the change immediately.

Personally I would set the TTL for the record to 60 minutes and leave it at that.