smartd double monitors devices when using symlinks to devices

[calestyo]

Forwarded from: ​https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=894134

Hi.

It seems that smartd "double monitors" devices, when explicitly naming them via
a symbolic link and using DEVICESCAN in the config file.

Consider e.g. the following typical use case:
One wants to monitor all devices, but has special settings (e.g. different temperature
ranges for one e.g. a SSD which runs at higher temps than an HDD):
/dev/disk/by-id/ata-Samsung_SSD_850_PRO_1TB_S252NXAG910017F -d auto -d removable -n standby,4 -a -W 0,50,60 -m root -M exec /usr/share/smartmontools/smartd-runner
DEVICESCAN -d auto -d removable -n standby,4 -a -W 0,45,50 -m root -M exec /usr/share/smartmontools/smartd-runner

It also makes sense to use the symbolic link /dev/disk/by-id/ata-Samsung_SSD_850_PRO_1TB_S252NXAG910017F
rather than e.g. /dev/sda, as the later is not necessarily a stable name.

However, with the above in smartd.conf, smartd output in syslog shows that
apparently both devices /dev/disk/by-id/ata-Samsung_SSD_850_PRO_1TB_S252NXAG910017F
and /dev/sda (which I assume is still auto-detected by the DEVICESCAN) are now
monitored (presumably with different monitoring settings).

Cheers,
Chris.

[Christian Franke]

This is already fixed since r4556, see ticket #313.

If the problem persists after upgrading to smartmontools 6.6, reopen this ticket and provide sample smartd log outputs.