Linode.com Forum

[knehcsa]

anywho.. i've been reading about server failovers and was wondering if this works:

Run BIND on two different servers (different datacenters, etc). Config the domain registrar to have one as a primary and one as a secondary dns server. Then, have the A address for the same domain (example.com) on each of the dns servers point to the ip of that server. (IE Server x's A entry points to it's ip, and Server y's A entry points to it's ip).

Does the same problem occur with Primary/Secondary DNS servers that occurs when trying to round robin dns and a server is offline??

IE. With round robin, if the dns server replies 1.2.3.1 and 1.2.3.2 and 1.2.3.1 is offline, the client won't try 1.2.3.2 (At least that's what all my testing has shown.) But, with primary/secondary dns server entries, i'm hopeing that just by the words used (primary/secondary) if the primary is unreachable, it will attempt the secondary)

Thanks,

Andrew

[Xan]

A lot of that would depend on caching. You can set the TTL of your DNS replies to some very small value, but that's not guaranteed to be honored by every server in the chain (IIRC).

[sednet]

knehcsa wrote:
Does the same problem occur with Primary/Secondary DNS servers that occurs when trying to round robin dns and a server is offline??


DNS server failover isn't a bit like DNS round robins.

DNS servers fail over from primary to secondary very nicely as long as your registrar has an accurate list of your DNS servers and that the right data is on the DNS servers it will just work.

DNS round robins ( by having multiple A records for a name ) are meant to spread load over many servers, not really for high availability.