[Dump-users] Resuming a verify after transient hardware failure

[Kenneth P. <sh...@se...>]

Is there a way to resume "restore -C" after a transient hardware read 
failure?

I'm backing up to an external USB NTFS drive, using compression. The 
resulting backup is about 150 gigabytes (after compression). After the 
backup I do a verify with "restore -C". For the last two full backups, I 
get a read error at sector 268435455 which turns out to be 0xFFFFFFF. I'm 
guessing this might be an issue either in the ntfs-3g FUSE filesystem or 
the underlying USB2 subsystem.

I'm able to read the sector fine with dd:

dd if=/dev/sdb of=/tmp/my.sector bs=512 count=10 skip=268435453

(Numbers chosen here to read a few blocks on either side of the claimed 
failing block.)

The kernel messages look like this:

Sep  5 15:41:37 segw2 kernel: sd 5:0:0:0: Device not ready: <6>: Current: 
sense key: Not Ready
Sep  5 15:41:37 segw2 ntfs-3g[22860]: ntfs_attr_pread: ntfs_pread failed: 
Input/output error
Sep  5 15:41:37 segw2 kernel:     Add. Sense: Logical unit not ready, cause 
not reportable
Sep  5 15:41:37 segw2 kernel:
Sep  5 15:41:37 segw2 kernel: end_request: I/O error, dev sdb, sector 
268435455
Sep  5 15:41:37 segw2 ntfs-3g[22860]: ntfs_attr_pread error reading 
'/Shelob/0/root/dump' at offset 132989304832: 4096 <> -1: Input/
Sep  5 15:41:37 segw2 kernel: Buffer I/O error on device sdb1, logical 
block 33554424