Re: failover and dns

From: Steven W. Engle (sengleat_private)
Date: Thu Apr 02 1998 - 13:04:08 PST

  • Next message: Garbrick, Randy: "RE: TIS Gauntlet : WINS and Exchange"

    >Dear All,
    >
    [snip]
    >
    >Company A now wants to improve resilliance. The have datacenters in
    >three
    >continents and so the basic idea is to put up three copies. Now the dns
    >entry will
    >point to one of them, if that fails then the contents of the dns will be
    >changed (not
    >by hand) to point at the secondary etc. Use a very short ttl on the dns
    >entry and
    >things should start again after a short while.
    
    It strikes me that a round-robin DNS might serve you well here. To my
    knowledge, round-robin DNS won't handle "if A fails then try B" -- it will
    cycle through all 'X' datacenters/sites, distributing the connections
    amoung them. In this scenario, if a particular site is not available, the
    user would have to try again later and most likely (with a short TTL) get
    sent to another site.
    
    Are there round-robin DNS implementations that perform "aliveness" tests
    and drops unavailable sites out of the round-robin?
    
    --
    Steven W. Engle                          Voice: (281) 333-9085
    Diversified High Technologies, Inc.        Fax: (281) 333-9087
    1350 Nasa Road One, Suite 105           http://www.dhtinc.com/
    Houston, TX  77058                    mailto:sengleat_private
    



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