having a super short TTL is a great way to overload your DNS servers and clients don't have to honor the TTL anyway and will often cache the records. IE caches records for 30 mins, I believe, for example.
On Wed, Nov 11, 2009 at 3:50 PM, Steven Alligood <[email protected]> wrote: > On 11/11/2009 03:35 PM, William Attwood wrote: > >> On Wed, Nov 11, 2009 at 3:27 PM, Steven Alligood<[email protected]> >> wrote: >> >> >> >>> On 11/11/2009 03:19 PM, William Attwood wrote: >>> >>> >>> >>>> Hello-- >>>> >>>> How does one accomplish geographical load balancing? With that in >>>> mind, >>>> what about geographical failover? Example, I have a data center (DC) in >>>> Dallas, and another in Salt Lake. How do I re-direct traffic if Dallas >>>> goes >>>> offline? >>>> >>>> Just a project I'm diving into. colo-specific load balancing and >>>> failover is accomplished, now we need to protect against the data center >>>> going offline, and speed of access to machines. I see how I can do >>>> geographical failover with a geographical load balancer, however, do I >>>> need >>>> 2 geographical load balancers if one of them goes offline? >>>> >>>> Has someone here worked on a project of this magnitude? >>>> >>>> >>>> >>>> >>>> >>> It';s been several years since I have set that up, but the old alteons >>> (now >>> owned by nortel) would do geographical load balancing with one in each >>> location. >>> >>> Basically, you setup your auth dns to point to each location, with any >>> subdomain in DNS delegated to the load balancer. It would then give out >>> dns >>> based on which one it found to be quicker, etc, and in an outage would >>> give >>> just itself out for it's local farm. >>> >>> Of course, if you are doing IPv6, check out the anycast stuff. Quite >>> amazing. >>> >>> -Steve >>> >>> >>> >> >> If one site goes offline, won't that mean 50% of my traffic also goes >> offline, depending on which IP DNS feeds back? I may have misunderstood >> you. >> >> >> > No, the dns for those particular subdomains have very short TTLs (like, 5 > seconds), so they expire quickly and have to be looked up again. So if your > site goes down between one web page serve and the next, it gets the DNS > entry for the site that is still online. > > > > > > /* > PLUG: http://plug.org, #utah on irc.freenode.net > Unsubscribe: http://plug.org/mailman/options/plug > Don't fear the penguin. > */ > /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
