This is my first post!  I don't really expect anyone to find this blog.

So I have a pretty big database (around 700 GB) and it's asynchronously mirrored to another location.  I thought it would be best to make the [PRIMARY] FileGroup as small as possible so I started with the unused data.  Since I really wasn't thinking, I just added a separate FileGroup and a data file so I can move the data to that file which is on RAID 50 (main data is on RAID 10).  All of a sudden, the mirror becomes SUSPENDED!  

Since the directory structure is not the same on either server, the database mirror doesn't know what to do with the extra data file which then results in a suspended mode.  You cannot just delete the data file/FileGroup to re-establish the mirroring so don't bother trying it.  The only thing you can do is redo the entire mirror.  Be sure to change the RESTORE DATABASE command to include the new data file(s) and use MOVE to their new directory.

That's the resolution to my issue.

If you can think of any other process to resolve this issue, please let me know!  Thanks!