Re: Crash a system with a standby unmounted disk and smartctl?

Hi David, I can’t see how an unmounted disk can cause a system crash.  Or perhaps I should say that I don’t think it *should* cause a system crash.  If it does, that indicates a kernel code bug or some strange hardware interaction/flaw.  Cheers, Bruce


> On Oct 5, 2015, at 11:04 PM, mathog <[email protected]> wrote:
> 
> One of my systems has 5 disks (U320 scsi, not RAID) on of which is a hot 
> spare, not mounted.  A while back one disk started to throw a lot of 
> errors, so the hot one was mounted and restored from backup, and the 
> failing one unmounted but left plugged in.
> 
> Later the bad disk was remounted briefly, to pull off a few files that 
> were updated on that disk after the last full backup.  After that was 
> done it was left hot but not (I believe) mounted.
> 
> There is a script on this system which periodically runs a long SMART 
> test on all hot disks, mounted or not.  This weekend the system crashed. 
>  The reason was, apparently that the failing disk had used up the spare 
> list:
> 
> kernel: sd 0:0:4:0: [sde] Unhandled sense code
> kernel: sd 0:0:4:0: [sde] Result: hostbyte=DID_OK 
> driverbyte=DRIVER_SENSE
> kernel: sd 0:0:4:0: [sde] Sense Key : Hardware Error [current]
> kernel: Info fld=0x1949399
> kernel: sd 0:0:4:0: [sde] Add. Sense: No defect spare location available
> kernel: sd 0:0:4:0: [sde] CDB: Read(10): 28 00 01 94 93 92 00 00 08 00
> kernel: end_request: I/O error, dev sde, sector 26514329
> 
> That was the last thing in the system log, time stamped at a point that 
> should have been roughly the end point of a full long SMART test.
> 
> This was quite an old kernel, 2.6.34.9.
> 
> So, as I said above, I'm not 100% sure that this failing disk wasn't 
> mounted.  If it was, the mount point would have been /tmp/sde, which 
> isn't a path anything on the system would have cause to look into.
> 
> Does the "no defect spare location available" error really cause a 
> system crash when it happens on a disk that isn't mounted, or must a 
> disk be mounted for this sort of error to crash the system?
> 
> Regards,
> 
> David Mathog
> [email protected]
> Manager, Sequence Analysis Facility, Biology Division, Caltech
> 
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-----------------------------------------------------------------------------------------------
Bruce Allen, Adjunct Professor of Physics
Leonard E. Parker Center for Gravitation, Cosmology and Astrophysics
Physics Department
University of Wisconsin - Milwaukee
3135 N Maryland Ave
Milwaukee, 53211 USA
Tel: +1 414-229-4474
Fax: +1 414-229-5589
[email protected]




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