Sun Directory Proxy 5.2 fail over?

Question

How do i set up DIR Proxy to fail over on the proxy end. I understand if a directory goes down, but what is the proxy goes down. How to i assure that the client will fail over to another proxy?

Answer 1

There are at least three options, in order of least to most desirable:
1. Have the client maintain a failover list of proxy servers. If it is unable to contact the first server in its local list, have it try the next server.
Pros: No additional network complexity or cost.
Cons: May not be possible unless you have access to client code; if proxy server addresses change or additional proxies are added, all clients configurations must be updated.
2. Use round-robin DNS. Point the client to the round robin address and let DNS determine which proxy server should be contacted.
Pros: Easy to implement on client side; load balances traffic equally across your proxy servers.
Cons: A proxy server failure will cause your clients to fail 1/nth of the time (where n is the number of proxy servers in the RR configuration).
3. Use an IP load balancing device (such as a Cisco Distributed Director or F5 BigIP) and have all clients point to the virtual IP of that device.
Pros: Automatically takes failed proxy servers out of the pool; additional load balancing configurations can be maintained on the hardware load balancing device. If you have redundant load balancers, a client should nearly always be able to connect.
Cons: Additional cost and network complexity