Disaster Recovery (DR) is replica of your production environment so that in case production environment goes down applicaiton can run from DR. So your application server, DB server and web apps everuthing is replcated to the different environment to different location. Everytime you make any changes in production code or DB perform those in DR as well. You can schedule SQL mirroring of prod data to DR data. DR switch to change connection pointers.

This question is quite unusual, but in ‘Product Development Company like XEROX’ it is expected at TECH LEAD level. I gave below answer in two phase :-1. Application DR System. 2. Database DR system.Application DR system could be handled on different DR server on different cluster and would automatically switch on after Main application URL did not respond until 150 seconds. The URL is automatically redirect to DR URL and serve the request. Please note this activity required following team:- • Development Team – For application hosting and configuration like SSL. • DNS / iDNS /IP Team - For URL redirecting and DNS entries. iDNS team may need to do Reverse Proxy setting after main server get live. • Security Team - For Venerability Scan.At Database DR Server, we need to perform below activities :- • Database Team - for Continuous (DELTA)database syncing (after couple of minutes). • Development Team – Ensure all web jobs and services are properly mapped. • Development Team – All SQL roles are properly defined.Finally, Any Third Party communication need to aligned with respective DR servers. Last but not least, NEVER forgot DR drill to ensure that everything is working as expected.