On Nov 27, 2012 7:34 AM, "Ralf Corsepius" <rc040203@freenet.de> wrote:
(snip)
> 2. dmesg reports this (Here: Fedora 16):
>
> [   26.904380] ata_id[762]: HDIO_GET_IDENTITY failed for '/dev/sdb': Invalid argument

Many - most? - USB to SATA bridge chips don't pass through these kind of requests. I suspect you would find that both hdparm and smartctl displaying similar results.  This can make life interesting.  For example, the drive could have exhausted the reserve of reallocateable sectors, leaving the OS to write bits on dead sectors and suffer transparent corruption.  The OS wouldn't know because it can't see the SMART values.

I'm not suggesting that symptomatic drive failure is necessarily involved with your described issue, but I *do* fsck far more often when smartd can't keep an eye on things for me.

--Pete