[CentOS] High Availability using 2 sites

Tom Brown tom.brown at goodtechnology.com
Thu Jan 5 14:16:12 UTC 2006


> I agree, BGP is important to route the IP's, but I've been exploring this
> same option with a different thought.  I'd like to hear what others say
> about this!
> 
> Here is my plan (although not implemented or tested) for Web Services.
> 
> At our main data center we have the primary DNS server and our primary web
> server.  The remote location houses the secondary DNS server and our
> secondary web server.  Also at that second location is "hidden" master DNS
> server.  Your registrar name records only point to the primary and
> secondary, therefore, the internet knows nothing of the hidden master.
> Then, the hidden master contains a similar set of DNS records that point to
> the secondary site.  Here's the trick!  The secondary DNS server syncs with
> the primary DNS server every x minutes.  If the secondary DNS server cannot
> communicate with the primary DNS server, it then looks at the "hidden"
> master DNS server and syncs the records (which is pointing at your secondary
> site).  Then, when your data center site comes back up, the secondary tries
> to communicate with the true master DNS server...it can...therefore it
> updates its records.
> 
> That is the theory in a nutshell.  I've read that this is possible, but I
> haven't had a chance to test it.
> 
> What do others think about this?  This is no substitution for BGP, but for
> those that don't run BGP or need to re-route the IP networks, this may work.

propagation




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