fsckmount: /dev/sdb1: can't read superblock
if fsck can't read the superblock also
# dumpe2fs /dev/hdd1
dumpe2fs 1.41.9 (22-Aug-2009)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 235d2897-72ab-4945-b443-30dc0eeeb3e0
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super large_file
Filesystem flags: signed_directory_hash
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 404000
Block count: 1614524
Reserved block count: 80726
Free blocks: 1039906
Free inodes: 344866
First block: 0
Block size: 4096
Fragment size: 4096
Reserved GDT blocks: 394
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 8080
Inode blocks per group: 505
Filesystem created: Sat Jan 1 16:15:12 2011
Last mount time: Thu Jan 13 11:57:19 2011
Last write time: Thu Jan 13 11:57:19 2011
Mount count: 3
Maximum mount count: 36
Last checked: Wed Jan 12 13:25:14 2011
Check interval: 15552000 (6 months)
Next check after: Mon Jul 11 13:25:14 2011
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: 5cfa5913-9096-4114-836b-7ee7bfaa00bf
Journal backup: inode blocks
Journal size: 128M
Group 0: (Blocks 0-32767)
Primary superblock at 0, Group descriptors at 1-1
Reserved GDT blocks at 2-395
Block bitmap at 396 (+396), Inode bitmap at 397 (+397)
Inode table at 398-902 (+398)
23777 free blocks, 4927 free inodes, 565 directories
Free blocks: 915-6143, 6225-20479, 20482-24575, 29253, 29258-29265, 29313-29316, 32582-32767
Free inodes: 3154-8080
Group 1: (Blocks 32768-65535)
Backup superblock at 32768, Group descriptors at 32769-32769
which should give an average backup superblock
# fsck --help fsck 1.41.9 (22-Aug-2009)
fsck.ext3: invalid option -- h
Usage: fsck.ext3 [-panyrcdfvtDFV] [-b superblock] [-B blocksize]
[-I inode_buffer_blocks] [-P process_inode_size]
[-l|-L bad_blocks_file] [-C fd] [-j external_journal]
[-E extended-options] device
Emergency help:
-p Automatic repair (no questions)
-n Make no changes to the filesystem
-y Assume "yes" to all questions
-c Check for bad blocks and add them to the badblock list
-f Force checking even if filesystem is marked clean
-v Be verbose
-b superblock Use alternative superblock
fsck -b 32768 -n -f -v /dev/DEVICE