Bill Larson wrote:
> As an aside, if their load balancer is the ONLY authoritative server,
> then what happens when this load balancer fails? Obviously, if the
> load balancer fails then no one can get to the host(s) that the
> balancer provides access to. But, if the load balancer also provides
> DNS information, then when the balancer fails then the result will be
> that the clients will get an "unknown host" type response rather than
> something that indicates that the host is unavailable. I would look
> at this as a situation where their solution is making communication
> less robust rather than more robust.
>

Hmmm... Most likely they'll get a timeout in either case, either the DNS
query will time out or the actual connection itself. Some clients will
probably be capable of distinguishing between the types of failures, and
others will not.

In any case, we use multiple load-balancer devices, in separate data
centers, with separate Internet connections, and they share state with
each other about their backend services. It's actually quite robust; I
don't recall a single instance where all of the load-balancers of a
"production" set were unavailable at the same time.

- Kevin