> If a 30 second delay is acceptable, even round robin dns forms a type of > failover. If the first ip fails, the browser tries the second, etc.
This is incorrect. IE does support some aliveness checking (http://www.geocities.com/tufansevim/dnsroundrobin.html) and will cycle through A records till it gets a response, but this is not specification and most dns resolvers and will not work for all clients. (http://www.acmebw.com/askmrdns/archive.php?category=81&question=359). Round Robin DNS should only be used in load sharing (it does not load balance) scenario until most DNS resolvers handle DNS SRV records, which will be the correct way for a DNS to provide failover. (http://www.isc.org/ml-archives/bind-users/2000/09/msg00350.html) LVS, as you mentioned, is an excellent solution. If you want to stay with a DNS solution then one of the Dynamic DNS servers may fit the bill, but your end up with other problems. - the name server propagation time you'll have - the problem of driving a lot of traffic to your DNS server because of the low TTL's. - DNS servers that don't honor TTL times that are too low - then giving out that bad info to it's users Christian Brink
