PRTG Manual: SNMP Linux Meminfo Sensor
The SNMP Linux Meminfo sensor monitors the memory usage of a Linux/Unix system using Simple Network Management Protocol (SNMP).
It shows the following :
- Available memory in absolute and percentage values
- Used physical memory (free memory plus buffer plus cache) in percent
- Free physical memory (free memory plus buffer plus cache) in bytes
- Used swap memory in percent
- Free swap memory in bytes
- Used memory on the whole system (physical memory plus swap) in percent
- Free memory on the whole system (physical memory plus swap) in bytes
Dutch: SNMP Linux meminfo, French: Info sur la mémoire SNMP Linux, German: SNMP Linux Speicherinfo, Japanese: SNMP Linuxメモリ情報, Portuguese: Linux Meminfo SNMP, Russian: Linux Meminfo по SNMP, Simplified Chinese: SNMP Linux 内存信息, Spanish: SNMP información de memoria Linux
- Knowledge Base: Checklist: Setting up SNMP on Linux
- For a general introduction to the technology behind SNMP, see section Monitoring via SNMP.
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.
On the details page of a sensor, click the Settings tab to change its settings.
Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. See below for details on available settings.
Basic Sensor Settings |
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Sensor Name |
Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets. |
Parent Tags |
Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here. |
Tags |
Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value. You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.
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Priority |
Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority). |
Sensor Display |
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Primary Channel |
Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor.
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Graph Type |
Define how different channels will be shown for this sensor.
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Stack Unit |
This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so. |
By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.
Scanning Interval |
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Click |
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Scanning Interval |
Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations. |
If a Sensor Query Fails |
Define the number of scanning intervals that a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:
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Schedules, Dependencies, and Maintenance Window |
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Schedule |
Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.
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Maintenance Window |
Specify if you want to set up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a Paused status instead. Choose between:
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Maintenance Begins |
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window. |
Maintenance Ends |
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the end date and time of the maintenance window. |
Dependency Type |
Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:
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Dependency |
This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend. |
Dependency Delay (Sec.) |
Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value.
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Access Rights |
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User Group Access |
Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:
You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.
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Channel Unit Configuration |
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Click |
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Channel Unit Types |
For each type of sensor channel, define the unit in which data is displayed. If defined on probe, group, or device level, these settings can be inherited to all sensors underneath. You can set units for the following channel types (if available):
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Knowledge Base: What SNMP sensors does PRTG offer?
Knowledge Base: My SNMP sensors don't work. What can I do?
Knowledge Base: Checklist: Setting up SNMP on Linux
To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see the Sensor Channel Settings section.
Click the Notification Triggers tab to change notification triggers. For detailed information, see the Sensor Notification Triggers Settings section.
For more general information about settings, see the Object Settings section.
For information about sensor settings, see the following sections: