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

[Christian Franke]

Christian Franke wrote:
> 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.
>

Sorry - this sets bit 2

>
>> 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

Same typo.