Input/output error on BluRay file cmp
I'm running Debian Squeeze on an older 32bit system that I'm using as a
file server. I use a BluRay writer to make compressed backups overnight.
However lately I've been having some problems. The initial cp seems to
work but when I do a cmp or rsync to test or fix cp errors, the writer
sometimes seems to go offline. It loses the ability to detect media in
the writer.
I can fix this by powering down the machine then starting it up again
(but not by rebooting - it needs a power off. Also, sync doesn't help).
I suspect that the media does have some bad parts that are causing
problems, but I'm not sure why they don't show up in the file copy, only
in the cmp. Sounds like the device isn't checking for write errors, only
complaining when it can't read.
The /etc/fstab entry for the device is: /dev/sr0 /media/dvd udf
user,rw,noauto,noatime 0 0
Here's a partial syslog sequence for a failed cmp which didn't cause the
writer to stop detecting media. I could still umount and mount the disc
again.
Feb 24 19:58:55 dellbert kernel: [ 631.756711] Buffer I/O error on
device sr0, logical block 7961400
Feb 24 19:58:55 dellbert kernel: [ 631.756758] Buffer I/O error on
device sr0, logical block 7961401
Feb 24 19:58:55 dellbert kernel: [ 631.756806] Buffer I/O error on
device sr0, logical block 7961402
Feb 24 19:58:55 dellbert kernel: [ 631.756854] Buffer I/O error on
device sr0, logical block 7961403
Feb 24 19:58:59 localhost kernel: [ 636.352066] sr 0:0:0:0: [sr0]
Device not ready
Feb 24 19:58:59 localhost kernel: [ 636.352071] sr 0:0:0:0: [sr0]
Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
Feb 24 19:58:59 localhost kernel: [ 636.352075] sr 0:0:0:0: [sr0] Sense
Key : Not Ready [current]
Feb 24 19:58:59 localhost kernel: [ 636.352080] sr 0:0:0:0: [sr0] Add.
Sense: Cannot read medium - incompatible format
Feb 24 19:58:59 localhost kernel: [ 636.352088] sr 0:0:0:0: [sr0] CDB:
Read(10): 28 00 00 79 7b 00 00 00 02 00
Feb 24 19:58:59 localhost kernel: [ 636.352097] end_request: I/O error,
dev sr0, sector 31845376
Feb 24 20:04:58 dellbert kernel: [ 995.351590] UDF-fs INFO UDF:
Mounting volume 'LinuxUDF', timestamp 2013/01/26 13:32 (1000)
Any ideas on why the device is losing the ability to detect media and
what I can do to get it back, other than shutting it down then starting
it up again?
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