Proper placement of file share witness

- The concept of a witness server may be familiar…to any of you who that are database administrators,…but for those that are not, a witness server…is a file share, that receives updates regarding…who has the most current version of the database.…Consider this scenario: we have two Exchange servers…in a DAG, both have been working together…and synchronizing for a long time.…One day the principal, or original copy…of the database, goes down for a few hours,…to run the newest cumulative update or something.…

When that server comes back online, it could…address the replica of the database and say "I'm back now.…"Go ahead and update yourself from my content."…The replica, that's been holding down the fort…while the principal was being updated,…believes itself to be the most complete database,…and should be considered the authority.…So this vote is now stuck at one to one,…unless a witness server steps in.…The witness server doesn't hold a copy of the database,…but it knows about the transactions, so it can verify…