Linux HA may not be the best choice in your situation. [CentOS]High Availability using 2 sites

[Tim Edwards]

Les Mikesell wrote:

> 
> 
> No, it describes what happens when a large number of clients are
> behind the same local DNS server - and not very realistically
> at that.

It describes what happens with a typical ISP where all the users are 
looking up addresses using the ISP's caching nameservers, this is not a 
local network. If it was a local network I was dealing with I could just 
have all the clients resolve off the one DNS server and there'd be no 
propagation delay. The problem with the Internet is the propagation 
delay out to all those seperate ISP's caching nameservers.

> What really happens is that the authoritative server will rotate
> the order of the list on each request, but downstream DNS servers
> and the client itself will cache a certain order once received.
> With a large number of clients connecting from a large number
> of places, the order distribution will be essentially random.
> Most client apps will try the first address in the list first
> and many won't continue if that fails.  The versions of IE
> that I've tested do try additional addresses although that
> might not happen the same way behind a web proxy.

Yes so because the order is disregarded with enough clients it will 
essentially be random. Its better than just having the single address I 
suppose, but its not necessarily redundant. It'd be good to know if its 
just IE that does this or other web browsers on other platforms.

-- 
Tim Edwards