title: Synology NAS: SMART Attributes per Disk
agents: snmp
catalog: hw/storagehw/synology
license: GPL-2.0-only
distribution: Sher Zaman
description:
 This Checkmk extension 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 needs no configuration.

 The service goes {CRIT} if DSM reports any SMART attribute with a status
 other than OK, with one exception. An attribute DSM reports as
 In_the_past fell below its threshold at some point in the drive's life
 and has since recovered. That history is held in the drive and cannot be
 cleared, so by default it does not affect the service state, though the
 attribute is still named in the service details every time it is seen.
 The state used for it, including {WARN} or {CRIT}, can be set with the
 rule set "Synology SMART attributes".

 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, so 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, for example {Disk 1}, {Drive 1} or
 {Drive 2 (DX517-1)} for disks in expansion enclosures. Bays are matched
 to disks on the slot number encoded in the device name. If a disk cannot
 be matched to a bay with certainty, the device path (for example
 {/dev/sda}) is used instead, so a drive is never given the wrong bay
 label.

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