Does my disk support SMART?

Question

I'm confused about this smartctl output. It says SMART status is not supported, but then it says it PASSED.

# sudo smartctl -H -d megaraid,24 /dev/sdb
smartctl 7.0 2018-12-30 r4883 [x86_64-linux-3.10.0-1160.59.1.el7.x86_64] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF READ SMART DATA SECTION ===
SMART Status not supported: ATA return descriptor not supported by controller firmware
SMART overall-health self-assessment test result: PASSED
Warning: This result is based on an Attribute check.

# echo $?
4

According to the man page, status code 4 means prefail Attribute is less than the danger threshold.

EXIT STATUS
...
...
    Bit 4: We found prefail Attributes <= threshold.

So I'm confused, is SMART data available on this disk or not?

Answer 1

With a hardware RAID controller like that, smartctl is querying the RAID controller, and the controller firmware is making the actual SMART queries to the physical disks.

The message:

SMART Status not supported: ATA return descriptor not supported by controller firmware
SMART overall-health self-assessment test result: PASSED
Warning: This result is based on an Attribute check.

means the smartctl is trying to say roughly: "The RAID controller is telling me a disk responded with something the controller did not fully understand and could not pass to me. Based on the parts of the response we both understood, the disk(s) seem to be OK... but the part that was not understood might have been important."

You might want to check the RAID controller's vendor support to see if there is a firmware update for the controller, possibly with updated SMART support.