Summary
The file system has become corrupted, and you have confirmed that the storage hardware and logs are ok, and that the lvm is correct.
The file system still refuses to mount complaining about a bad superblock on a specific disk drive.
Solution
You can attempt to fix the bad superblock with the xfs_repair command.
For example:
# xfs_repair /dev/sdb
If you are still experiencing problems with the a superblock, and the above command suggests that there is log data that needs replaying, you can attempt to clear out the logs and fix the disk using xfs_repair -L.
WARNING! Use this command only as a last resort. This command may lose or corrupt all your data.
For example:
# xfs_repair -L /dev/sdb |
