Disaster recovery is one of those things we hope will never happen, and in many cases we act like it never will happen. But when that horrible day comes you better believe a good tested plan will pay off in spades. Most people find it scary because they really don’t know where to start, so work thru these steps to get started
What is my SLA? If you don’t have an SLA this will be your first task, if you do have an SLA then move on.
If my SLA is under 8 hours then I need a Hot Stand by Farm, if my SLA is over 8 hours but under 24 hours then I need a Warm Stand by Farm, and if my SLA is above 24 hours then I need a Cold Stand by Farm.
Contact your internal teams or Hardware vendors to understand the cost of the new servers, router, NLB’s, etc and any configuration that will happen.
Now review and insure that your budget and SLA work together, if not you have to either agree to spend money in line with the SLA or reduce your SLA to match the budget.
Now go and plan then deploy your Disaster recovery environment
Then test your Disaster Recovery on a regular basis, while testing think about this for some reason you may not be able to perform the recovery so you should have great documentation that can be handed to somebody else (Possibly without SharePoint knowledge) and they should be able to perform the recovery just following those notes.
NOTE: This process should take several months or up to a year to get to step #6. These steps are the core points that will get you to the end and if you focus on getting thru them all the other steps in between will take care of themselves.
Here are some great articles that you can use to help plan with your disaster recovery planning.
Configure and manage SQL Server availability groups for SharePoint Server