What are some of the industry standard enterprise software to allow fail-over or swap-over between 2 servers?
E.g., if 1 server goes down(due to connection or power, etc), the other kicks in either immediately, or after a certain time of like a few mins
I have 2 Windows Server 2012 servers, and 2 Windows Server 2008R2 servers. What software should I consider for each of the setup?
You can use Network Load Balancing (NLB), it's built in Windows, and works with standard version.
You will end with a virtual IP Address, to which client will connect.
It's IP based, so it won't detect if your web server or application stop. It will spread load against all servers until one of them is disconnected from network or dead.
You can use affinity to keep client connected on same node (hash between IP of client and virtual)
It may require special configuration on your switch, depend on setup your will choose (unicast vs multicast).
If you also need to share data (shared windows disk through san), then you must look on Windows Failover Clustering. It's more advanced (using resource) , but need a shared storage solution.
Then you can also look for third party solution like Double take, Safekit & co.
You badly defines your needs. You choose a solution based on what will the servers hosts (web sites, mailboxes, dns, databases, custom app...).
Mainly, the solution should be designed to work in high availability, else you will experience issue and won't be supported by the software vendor in case of issue or questions.
Windows Server offers this natively, it's called Microsoft Cluster Services.
/edit : Mathieu makes the good point that you might do just fine with MS NLB, depending on the service(s) that you're trying to make highly available.
