The first way to try to recover the current volume would be to
overwrite LBA 2262535088 which you should only do with the filesystem
unmounted. That's the sector causing the read error. If this is a 512
byte drive:
dd if=/dev/zero of=/dev/sdb count=1 seek=2262535088
It is a 512 byte drive.
Unfortunately overwriting that fails - which is quite weird, given that
there are 0 reallocated sectors, according to SMART.
Is there a way to determine what's stored there (i.e. if it's a file?).
# dd if=/dev/zero of=/dev/sdb count=1 seek=2262535088
dd: writing to `/dev/sdb': Input/output error
1+0 records in
0+0 records out
0 bytes (0 B) copied, 2.88439 s, 0.0 kB/s
# dmesg -c
[ 8177.713212] ata4.00: exception Emask 0x0 SAct 0x400 SErr 0x0 action
0x0
[ 8177.713285] ata4.00: irq_stat 0x40000008
[ 8177.713349] ata4.00: failed command: READ FPDMA QUEUED
[ 8177.713419] ata4.00: cmd 60/08:50:b0:8b:db/00:00:86:00:00/40 tag 10
ncq 4096 in
[ 8177.713419] res 41/40:08:b0:8b:db/00:00:86:00:00/00 Emask
0x409 (media error) <F>
[ 8177.713662] ata4.00: status: { DRDY ERR }
[ 8177.713725] ata4.00: error: { UNC }
[ 8177.755099] ata4.00: configured for UDMA/133
[ 8177.755175] sd 3:0:0:0: [sdb]
[ 8177.755252] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[ 8177.755318] sd 3:0:0:0: [sdb]
[ 8177.755380] Sense Key : Medium Error [current] [descriptor]
[ 8177.755449] Descriptor sense data with sense descriptors (in hex):
[ 8177.755516] 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
[ 8177.755600] 86 db 8b b0
[ 8177.755667] sd 3:0:0:0: [sdb]
[ 8177.755729] Add. Sense: Unrecovered read error - auto reallocate
failed
[ 8177.757316] sd 3:0:0:0: [sdb] CDB:
[ 8177.757377] Read(16): 88 00 00 00 00 00 86 db 8b b0 00 00 00 08 00 00
[ 8177.757463] end_request: I/O error, dev sdb, sector 2262535088
[ 8177.757542] ata4: EH complete
--
Tomasz Chmielewski
http://www.sslrack.com
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