disk or cable error? (CAM status: ATA Status Error)

Dave freebsd01 at dgmm.net
Mon Aug 27 14:54:21 UTC 2018

On Monday 27 August 2018 12:46:36 tech-lists wrote:
> On 26/08/2018 16:01, ixbug at riseup.net wrote:
> > Do any of these errors provide hints as to whether this is a disk
> > error affecting both at the same time or broken cable? (both disks
> > are connected to the mainboard via the same cable)
> these values:
> 5 Reallocated_Sector_Ct
> 196 Reallocated_Event_Count
> 197 Current_Pending_Sector
> 198 Offline_Uncorrectable
> are all zero for both disks, so if these remain zero after a successful 
> long test with *no LBA errors* then that would seem to me at least to 
> indicate there's no problems with the disks themselves. If, in the face 
> of those results, this persisted:
> > (ada1:ahcich1:0:0:0): WRITE_FPDMA_QUEUED. ACB: 61 08 90 a4 aa 40 1d 00 00 00 00 00
> >  (ada1:ahcich1:0:0:0): CAM status: ATA Status Error
> >  (ada1:ahcich1:0:0:0): ATA status: 41 (DRDY ERR), error: 10 (IDNF )
> then yeah I'd say bad cable/bad interface

IME "199 UDMA_CRC_Error_Count" at zero generally means the
SATA cable is fine.  A failing cable that works most of the
time almost always results in an ever increasing CRC Error
Count.  No guarantees, obviously, but it moves the odds in
favour of something else being the problem.

I have seen cheap nasty SATA cables result in no CRC Error
Count but the drive dropping off the system.  It can be cured
temporarily by plugging/unplugging the connector a few times
to "scrape clean" the contacts.  I would guess it's two
different metals reacting poorly with each other, especially
in a humid environment.

Having said that, even decent SATA cables are cheap and it
can't hurt to try replacing them first if diagnostics can't
point to a specific cause.

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