Manipulating the Round robin

[Radi Tzvetkov]

Kevin,
I am trying to get a failover site. All the requests must be served from A,
when A fails all the customers are going to B (which is a day or two behind
A). One thing i tried is to hand 2 IPs and make sure client goes to A, if A
timeouts browser goes to B automagically.

Any ideas on how to get this resolved?

Thanks




2008/1/14, Kevin Darcy <kcd at chrysler.com>:
>
> Radi Tzvetkov wrote:
> > Hello list,
> > I am trying to find more information on how to manipulate the round
> robin.
> > I have a website.com that responds with 1.1.1.1 and 2.2.2.2 and these
> are
> > load balanced via round robin.
> > is there any way to manipulate the round robin and have the web site
> return
> > the IPs in the same order every time?
> >
> > say disable the round robin?
> >
> >
> Yes, there is (see rrset-order and/or sortlist), but before you start
> down that path, realize that *any*other*resolver* that caches the
> information is going to employ whatever sorting algorithm it deems
> appropriate, when answering from its cache, which in many cases reduces
> to round-robin as the Lowest Common Denominator. Manipulating the order
> of address records only works reliably, therefore, when you control
> *all* the resolvers between the client and the authoritative
> nameservers. This is not feasible for Internet names, but has limited
> applicability to some intranets where the resolvers are all under
> central control.
>
> You can defeat caching somewhat by lowering your TTLs to anti-social
> levels, but do you really want to be that rude and impolite, not to
> mention squandering your own nameserver resources?
>
> My other question would be: what are you trying to achieve by having the
> addresses be given out in the same order every time? Do you have one
> "strong" server and one "weak" server? How then is the "weak" server
> going to handle the load if the "strong" server fails? Generally
> speaking, it's a better strategy to beef up both servers to
> approximately the same capacity, and then use simple round-robin, or a
> commercially-available load-balancing solution, to split up the load
> approximately equally between them. If one of the servers fails, at
> least then you have a fighting chance of the other server being able to
> handle the load.
>
>
>                                     - Kevin
>
>
>
>


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Best Regards
Radi Tzvetkoff