title: Synology NAS: SMART Attributes per Disk
agents: snmp
catalog: hw/storagehw/synology
license: GPLv2
distribution: Sher Zaman (FirmaTrust)
description:
 This check monitors the SMART attributes of every physical disk in a
 Synology NAS via SNMP (SYNOLOGY-SMART-MIB, .1.3.6.1.4.1.6574.5). It works
 on DSM 6.2 and later and requires no configuration.

 The service goes {CRIT} if DSM reports any SMART attribute with a status
 other than OK.

 In addition, the raw values of the pre-failure counters
 Reallocated_Sector_Ct, Current_Pending_Sector, Offline_Uncorrectable,
 Reported_Uncorrect and UDMA_CRC_Error_Count are checked against
 thresholds (default: {WARN} at 1 or more, {CRIT} at 10 or more). Each
 counter is only evaluated on drives that actually report it; a missing
 attribute is never flagged. The thresholds can be adjusted per service
 with the rule set "Synology SMART attributes".

 A rising Reallocated_Sector_Ct, Current_Pending_Sector or
 Offline_Uncorrectable indicates a failing disk. UDMA_CRC_Error_Count
 usually points to a cabling or backplane problem rather than the disk
 itself.

 Power_On_Hours is reported informationally and recorded as a metric.
 Disk temperature is intentionally not covered as it is already handled
 by the built-in Synology disk check.

item:
 The drive bay as reported by DSM, e.g. {Drive 1} or {Drive 2 (DX517-1)}
 for disks in expansion units. If the SMART table and the disk table
 disagree on the number of disks, the device path (e.g. {/dev/sda}) is
 used instead.

discovery:
 One service is created for every disk found in the SMART table.
