I'm moving a domain's nameservers from the registrar to dnsmadeasy.com so that we can have automatic failover (among other benefits). When I've done this in the past I simply set the TTL value as low as it can go (1 minute) for the A record so that upon failure of the primary server the backup server is (nearly) immediately online.
The only issue that I can find with a low TTL is that we will have "higher query traffic". Is this a bad thing? Contrarily, are there benefits to using a high TTL value?
Best Answer
You're right, the main disadvantage of using a low TTL is that you'll end up dealing with a higher query load than with higher TTL. That said, as long as your DNS host doesn't have any problems with handling the additional load, then go ahead. Honestly, if they had concerns about their ability to handle the load, they wouldn't let you set a very low TTL for your records (though many do tend to recommend that you set your TTL only as low as is necessary, which is a sound recommendation due to the user-experience point that ceejayoz made).
Additionally, I should mention that many ISPs DNS resolvers completely ignore the TTL setting and just set their own cache expiry on records, so for many cases, changing the TTL won't actually make any difference in the amount of queries that end up hitting the authoritative servers for your domain.