mmm not really but thanks anyway.
I've run xfs_repair on the unmounted array and it spews out a ton of error messages and eventually fails...
corrupt dinode 4345, extent total = 1, nblocks = 0. This is a bug.
Please capture the filesystem metadata with xfs_metadump and
report it to firstname.lastname@example.org.
cache_node_purge: refcount was 1, not zero (node=0x7f80593d8fc0)
fatal error -- 117 - couldn't iget disconnected inode
the resulting array can be mounted but the contents are total garbage and it seems that i've lost my 6TB of data!!!