[smartmontools-support] exit-code 4, what does it mean and why?

[Christian Franke]

Stefan K wrote:
> in our Dell-Server I got the exit-code 4, so far as I can see it means some thing is wrong "Bit 4: We found prefail Attributes <= threshold.".

This would be exit status 16 (0b00010000) , so bit 4 is not set.

Exit status 4 (0b00000100) means: "Bit 2: Some SMART or other ATA 
command to the disk failed, ..."


>   Can somebody tell me please why, which attribute it is (the other disk has nearly the same attributes)? Thanks in advance..
>
> smartctl --xall -d megaraid,0 /dev/bus/0 ; echo $?
> smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.10.0-18-amd64] (local build)
> Copyright (C) 2002-20, Bruce Allen, Christian Franke,www.smartmontools.org
>
> === START OF INFORMATION SECTION ===
> Model Family:     Dell Certified Intel S4x00/D3-S4x10 Series SSDs
> Device Model:     SSDSC2KB480G7R
> ...
>
> === START OF READ SMART DATA SECTION ===
> SMART Status not supported: ATA return descriptor not supported by controller firmware

The SMART STATUS command failed due to a known limitation (bug) of the 
SAT layer of the RAID controller firmware. This sets bit 4. This does 
not indicate a disk problem.


> SMART overall-health self-assessment test result: PASSED
> Warning: This result is based on an Attribute check.

Starting with smartmontools 7.3, bit 4 is no longer set in this case if 
the above attribute check succeeded, see:
https://www.smartmontools.org/ticket/1441


Regards,
Christian