device_overrides protocol "scsi" is not passed to smartctl during polling (Samsung T7 USB SSD)

[KruseLuds]

Summary

I found what appears to be a bug in the agent when using device_overrides with a Samsung T7 USB SSD.

The override is recognized by the agent, but the configured protocol is not passed to smartctl during polling.

If you'd like, I'm happy to test a development build on this hardware -

Environment

• SMART Sniffer Agent: v0.5.16
• OS: Debian Bookworm (arm64)
• smartmontools: 7.3
• Device: Samsung PSSD T7 1TB
• Device path: /dev/sda

Discovery

Automatic discovery does not find the drive:

sudo smartctl --scan-open

returns no drives.

Manual SMART access

The drive is accessible when explicitly using the SCSI transport:

sudo smartctl -d scsi -a /dev/sda

This returns:

• SMART support available
• SMART support enabled
• SMART Health Status: OK

Configuration

I added the following override:

device_overrides:
  - device: /dev/sda
    protocol: scsi

Agent log

The agent recognizes the override:

added override device: /dev/sda (protocol: scsi)

However, immediately afterwards it logs:

WARNING: smartctl -a /dev/sda failed (exit code 1: command line parse error)

API output

The drive is created:

{
  "id":"dev-sda",
  "device_path":"/dev/sda",
  "protocol":"scsi"
}

but the returned SMART JSON shows the executed command was:

smartctl --json -a /dev/sda

instead of:

smartctl --json -d scsi -a /dev/sda

The returned JSON includes:

/dev/sda: Unknown USB bridge [0x04e8:0x4001 (0x100)]

which is expected when -d scsi is omitted.

Expected behavior

When a drive is configured with:

device_overrides:
  - device: /dev/sda
    protocol: scsi

the polling command should include the configured transport:

smartctl --json -d scsi -a /dev/sda

instead of:

smartctl --json -a /dev/sda

That would allow SMART polling to succeed for this Samsung T7. FYI, from the RPI4 host command line:

pi@kruse-pi:~$ sudo smartctl --json -d scsi -a /dev/sda
{
  "json_format_version": [
    1,
    0
  ],
  "smartctl": {
    "version": [
      7,
      3
    ],
    "svn_revision": "5338",
    "platform_info": "aarch64-linux-6.1.0-51-arm64",
    "build_info": "(local build)",
    "argv": [
      "smartctl",
      "--json",
      "-d",
      "scsi",
      "-a",
      "/dev/sda"
    ],
    "exit_status": 4
  },
  "local_time": {
    "time_t": 1785518199,
    "asctime": "Fri Jul 31 13:16:39 2026 EDT"
  },
  "device": {
    "name": "/dev/sda",
    "info_name": "/dev/sda",
    "type": "scsi",
    "protocol": "SCSI"
  },
  "scsi_vendor": "Samsung",
  "scsi_product": "PSSD T7",
  "scsi_model_name": "Samsung PSSD T7",
  "scsi_revision": "0",
  "scsi_version": "SPC-4",
  "user_capacity": {
    "blocks": 1953525168,
    "bytes": 1000204886016
  },
  "logical_block_size": 512,
  "scsi_lb_provisioning": {
    "name": "fully provisioned",
    "value": 0,
    "management_enabled": {
      "name": "LBPME",
      "value": -1
    },
    "read_zeros": {
      "name": "LBPRZ",
      "value": 0
    }
  },
  "rotation_rate": 0,
  "logical_unit_id": "0x5000000000000001",
  "serial_number": "Y390104T0SNBX6S",
  "device_type": {
    "scsi_terminology": "Peripheral Device Type [PDT]",
    "scsi_value": 0,
    "name": "disk"
  },
  "smart_support": {
    "available": true,
    "enabled": true
  },
  "temperature_warning": {
    "enabled": false
  },
  "smart_status": {
    "passed": true
  },
  "temperature": {
    "current": 0
  },
  "scsi_temperature": {
    "drive_trip": 0
  }
}
pi@kruse-pi:~$ 

If you'd like, I'm happy to test a development build on this hardware.

[KruseLuds]

I have supplied a fix which was tested and I am using it now successfully - for anyone else that also needs this fix - in case it is not implemented (if my pull request just sits there forever) - here is the fixed version: https://github.com/KruseLuds/smart-sniffer

[spry-salt]

Hoping this integration is still active?