Disk (Local API, SNMP, WMI) service

When this service has a scan interval of less than 5 minutes, the agent may take longer than the scan interval to gather the metrics. As a result, you may notice some scan intervals are not populated.

The Disk service monitors a hard disk for its used, free, and total disk space. If a drive name is not found, the drive will appear misconfigured. For example, if you are monitoring a USB drive or similar removable drive that is removed.

Service TypeLocal API, SNMP, and WMI
Instances on a Device15
Device Class for Disk (Local API)Server - Generic, Workstation - Generic, Laptop - Windows, Server - Windows, and Workstation - Windows
Device Class for Disk (SNMP)Server - Generic, Workstation - Generic, Other, Printer, Scanner/Camera, Switch/Router, Laptop - Windows, Server - Windows, and Workstation - Windows
Device Class for Disk (WMI)Laptop - Windows, Server - Windows, and Workstation - Windows
Monitored ByAgent (Windows, Red Hat Enterprise Linux, and macOS 10.4 and higher) and Windows probe (SNMP and WMI)
Scan Interval60 minutes
Minimum Scan Interval1 minute
Drive Designation LetterThe letter of the hard disk or partition to monitor. For example, C: or D:.
Volume Index (SNMP only)The index of the SNMP object representing the partition of hard disk to monitor.

Properties queried and calculations performed (WMI only)

WMI ClassWin32_LogicalDisk
WMI Property 0Size
WMI Property 1FreeSpace

To configure Volume Name or Volume Index, walk the . SNMP OID on the target device's IP address to determine which disks are available for monitoring.

. "A:\"

. "C:\ Label: Serial Number 74ebc3fb"

. "D:\ Label:SP2POEM_EN Serial Number 356563d9"

. "Virtual Memory"

OID/Calculation (SNMP only)

N-able N-central services use Reverse Polish Notation (RPN) for all calculation formulae.

Metric NameOID/CalculationDescription
Total Disk Size(Total Disk Size x $hrStorageAllocationUnit) / 1024

The size of the disk.



Disk Space Used(Disk Space Used x $hrStorageAllocationUnit) / 1024

The amount of space used on the disk.


Disk Free Space[(Total Disk Size - Disk Space Used) x $hrStorageAllocationUnit] / 1024The unoccupied space on the partition or disk.
Disk Usage (%)(Disk Space Used / Total Disk Size) x 100The percentage of space used on the disk.