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.



Attachment: smime.p7s
Description: S/MIME Cryptographic Signature

/*
PLUG: http://plug.org, #utah on irc.freenode.net
Unsubscribe: http://plug.org/mailman/options/plug
Don't fear the penguin.
*/

Reply via email to