Global Load Balancing / Failover....what about dns entries being cached?

[clayton-price]

It is my understanding that DNS is used to provide data center redundancy. How does one resolve the problem of dns entries being cached across the Internet? For example, I fail-over to my secondary datacenter, the IP addresses of my primary datacenter will likely be cached in dns servers across the Internet. What are some options for datacenter redundancy that can overcome these issues of dns propogation delays?

Thanks!

[shamilton-wilkes · Accepted solution]

There's no real fix for caching. You can set your TTL to 15 minutes to minimise the problem but that's about it.

[ahojmark]

The only option that you have is to run with a low TTL.

Unfortunately, there are applications out that that don't behave very well to a low TTL. Microsoft Internet Explorer, for example, needs to be restarted for it to do another name lookup. The same holds true for some proxies etc.

-A