PRTG Manual: Disk/Storage
The Disk/Storage monitor allows you to monitor the used percentage of a devices available disk/storage space. When a disk monitor runs, the monitor requests the current percentage of disk space used from the monitored devices. These results are compared with the monitors specified thresholds.
The Disk monitor editor contains the following tabs that require configuration: Settings, Devices, Schedule, Event, and History.
The Schedule, Events and History settings are the same for all monitor types. See Configuring Monitors for more information about configuring these settings. For the other tabs see the information below.
Name
The Monitor name is the name of the monitor used to refer to the monitor in the monitors list view, and in monitor events and notifications. Monitor names must not be unique but it is recommended you use unique names to differentiate them.
Threshold
The Disk/Storage monitor threshold specifies the Percentage of Used Disk Space that would produce a down and warning state. The warning level must be less than or equal to the critical level. The warning and critical levels must be between 0 and 100.
The devices tab allows you to select which devices and their respective Disks to monitor. The Disk monitor can monitor 1 or more Disks on a device depending on what Disk information is available on that device.
To add devices/disks to the monitor select the 
button in the lower left corner. A device selector will be presented allowing you to choose one or more devices to monitor. When the device is selected each of the devices physical Disks will be added to the monitor. Note: Only devices with an assigned SNMP or WMI credential will be available in the picker. If you do not see a device ensure it has the appropriate credential assigned.
To edit which Disks on a device to monitor. Select the device or one of its disks in the list and press the edit button 
. A list of all of the devices available disks will be presented. Check the disks you would like to monitor and close the dialog. The monitored disks list will be updated to reflect the changes. Note: If a disk is not available it could be because it was not discovered during device discovery. To update the list ensure valid credentials are available and rediscover the device. See Monitored Devices for more information.
To remove a device or disk from the monitor select the device or disk in the list and press the delete button 
. The device/disk will be removed from the monitor.
Note: UVexplorer is able to collect the disk information using either the SNMP protocol or on windows machines using the WMI protocol. When selecting a disk to monitor the entry in the list will indicate which protocol was used to collect that information. If a windows machine has both an SNMP and WMI agent enabled with valid credentials for each, then the disk information could be collected using both protocols. If this occurs each disk will have two entries in the monitor selection list, one for each protocol. This is done to allow you to specify which protocol you would like to use to collect the information. If the agents are written correctly the information should be the same for either. We recommend, and will choose by default, the SNMP protocol since it is usually quicker.
See Monitor Device Picker for more information on choosing devices.
