smartctl on Synology system fails to scan for devices

[Starttoaster]

I'm trying to get smartctl_exporter working on a Synology NAS. I haven't looked into the scan logic yet, but will soon. The exporter shows that it's found 0 devices in the scan though I have 4 SATA disks installed in the NAS. The disks show up in fdisk as /dev/sata{1-4}.

smartctl version: smartmontools release 7.4 dated 2023-08-01 at 10:59:45 UTC
smartctl_exporter version: (version=0.13.0, branch=HEAD, revision=2424bcba0dc3e2a326d3937304f4ff63efc36a2c)"

Startup logs:

~$ sudo /opt/smartctl_exporter/smartctl_exporter --smartctl.path="/usr/local/bin/smartctl7" --log.level=debug

time=2025-03-09T01:09:12.006Z level=INFO source=main.go:187 msg="Starting smartctl_exporter" version="(version=0.13.0, branch=HEAD, revision=2424bcba0dc3e2a326d3937304f4ff63efc36a2c)"
time=2025-03-09T01:09:12.006Z level=INFO source=main.go:188 msg="Build context" build_context="(go=go1.23.4, platform=linux/amd64, user=root@57b5cad14fb8, date=20241220-06:37:30, tags=unknown)"
time=2025-03-09T01:09:12.006Z level=DEBUG source=readjson.go:83 msg="Scanning for devices"
time=2025-03-09T01:09:12.029Z level=INFO source=main.go:198 msg="Number of devices found" count=0
time=2025-03-09T01:09:12.029Z level=INFO source=main.go:213 msg="Start background scan process"
time=2025-03-09T01:09:12.029Z level=INFO source=main.go:214 msg="Rescanning for devices every" rescanInterval=10m0s
time=2025-03-09T01:09:12.030Z level=INFO source=tls_config.go:347 msg="Listening on" address=[::]:9633
time=2025-03-09T01:09:12.030Z level=INFO source=tls_config.go:350 msg="TLS is disabled." http2=false address=[::]:9633

For some background, I can run smartctl7 -a /dev/sataX -json on any of the drives and get SMART data back. And smartctl is in an unusual path because Synology bundles smartmontools 6.5, and smartmontools 7+ is only available in a community package.

[Starttoaster]

After looking closer at the code, and replicating the logic there, smartctl7 --scan --json appears to return 0 devices. I've tried every combination of the --smartctl.device-include values from the smartmontools device man page https://linux.die.net/man/8/smartctl
and still get 0 devices.

However, the exporter works if I pass in all my disks with --smartctl.device="/dev/sata1" --smartctl.device="/dev/sata2" --smartctl.device="/dev/sata3" --smartctl.device="/dev/sata4" so that's something at least.

Any ideas on how to get a good scan from smartctl? If not, we can just close the Issue since it appears to be more related to synology and smartmontools than with this exporter.