I currently have a two node exchange 2010 cluster and I file share witness all in different data centers, both hosts run server 2008 R2 are apart of the same dag with fail-over work fine. I need to add a third node to the dag which also comes from a different data center but I'm having a few issues. One by adding the node I will violate the file share majority rules with an even number, three hosts and one witness. I considered removing the witness but this doesn't work, it Exchange 2010 will not allow it. I've considered adding a second file share witness but I don't believe that will work as the second file share witness only acts as a backup to the current active file share witness.
I have other thoughts, but apparently I may do better asking someone else. If you can please help!