The problem is that the ISP that the server is connected to is very unreliable.
So I purchased another IP address from another ISP. Now I have two different
connections to the internet, on totally separate networks. I also happen to have
another server. I connected the second network connection to my spare server.
I understand that I can use DRBD, heartbeat, ipfail, and MySQL
replication to make sure that both computers are able to serve requests.
This would mean, for instance, that if the first server were dead, and a client happened
to make a request on the second IP (through the luck of a round-robin A record draw),
then he would be able to write records to the database, view the web site/forums, etc.
But still, the basic problem is that user's DNS servers all over the world are caching
both public IP addresses as A records.
Half the requests that clients make will go to a dead server, if a node has died.
Sure I can use heartbeat to take over services, but still, what is done to avoid having
client requests (from outside my network) go into a black hole?
Sorry for such a simple question. The only thing I can see is to put a 60 second TTL on
the DNS record. Then, if a node is down, I can republish the DNS tables to not include the dead node.
But even so, that means that for up to 60 seconds, some requests will go to a black hole.
Harold
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