Couldn’t mount AIX file system. First information says that media is not formatted

I had a problem mounting a file system after the server rebooted. At first it reported that the logical volume wasn’t formatted or the format is incorrect. Then it asked to run fsck.

root@aix5:/ # mount /fallback
Replaying log for /dev/fallback.
mount: 0506-324 Cannot mount /dev/fallback on /fallback: The media is not formatted or the format is not correct.
0506-342 The superblock on /dev/fallback is dirty.  Run a full fsck to fix.

I just ran fsck on the logical volume and then mounted the file system.

root@aix5:/ # fsck /dev/fallback

The current volume is: /dev/fallback
**Phase 1 – Check Blocks, Files/Directories, and Directory Entries
**Phase 2 – Count links
**Phase 3 – Duplicate Block Rescan and Directory Connectedness
**Phase 4 – Report Problems
**Phase 5 – Check Connectivity
**Phase 7 – Verify File/Directory Allocation Maps
**Phase 8 – Verify Disk Allocation Maps
15728640 kilobytes total disk space.
63 kilobytes in 30 directories.
7664455 kilobytes in 438 user files.
8061172 kilobytes are available for use.
File system is clean.
Superblock is marked dirty; FIX? y
All observed inconsistencies have been repaired.

root@aix5:/ # mount /fallback

root@aix5:/ # df -g /fallback
Filesystem    GB blocks      Free %Used    Iused %Iused Mounted on
/dev/fallback      15.00      7.69   49%      470     1% /fallback