Now I don’t want to get into the details of Quorum, there are plenty of great posts out there that explain it far better than I can but in a nutshell, each node in the cluster has a vote and we really want the total number of votes to be an odd number. But we’ve only got two servers, does that mean that we need a create another server to make an odd number? Well, no we don’t. What we can use is what’s known as a file share witness, and that’s simply a file share that each of the nodes in the cluster can access. That file share will effectively act as our third vote.
So first thing that you’re going to need to do is create a file share somewhere, the best place for that in our setup would be on the domain controller or somewhere that we know is always likely to be available. So go and do that now, call it what you like but make sure that the servers are going to have full rights to it. As this is just our own personal little test lab and we’re not too worried about best practices you could possibly open it up to EVERYONE (probably not a great idea in a production environment but not the end of the world if we want to be lazy in our own little play pen).
David also shows how to set up an Availability Group.