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 Type | Local API, SNMP, and WMI |
| Instances on a Device | 15 |
| 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 By | Agent (Windows, Red Hat Enterprise Linux, and macOS 10.4 and higher) and Windows probe (SNMP and WMI) |
| Scan Interval | 60 minutes |
| Minimum Scan Interval | 1 minute |
| Drive Designation Letter | The 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)
| Namespace | root\cimv2 |
| WMI Class | Win32_LogicalDisk |
| WMI Property 0 | Size |
| WMI Property 1 | FreeSpace |
To configure Volume Name or Volume Index, walk the .1.3.6.1.2.1.25.2.3.1.3 SNMP OID on the target device's IP address to determine which disks are available for monitoring.
.1.3.6.1.2.1.25.2.3.1.3.1 "A:\"
.1.3.6.1.2.1.25.2.3.1.3.2 "C:\ Label: Serial Number 74ebc3fb"
.1.3.6.1.2.1.25.2.3.1.3.3 "D:\ Label:SP2POEM_EN Serial Number 356563d9"
.1.3.6.1.2.1.25.2.3.1.3.4 "Virtual Memory"
OID/Calculation (SNMP only)
N-able N-central services use Reverse Polish Notation (RPN) for all calculation formulae.
| Metric Name | OID/Calculation | Description |
|---|---|---|
| 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] / 1024 | The unoccupied space on the partition or disk. |
| Disk Usage (%) | (Disk Space Used / Total Disk Size) x 100 | The percentage of space used on the disk. |