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memory (System)


Hierarchy Level


Configure the memory monitoring system on your PTX Series and MX Series devices. The memory monitoring system on your device monitors anomalies with respect to the memory utilization of Junos applications and overall system in the control plane of your device. Apart from monitoring the system memory, you can also configure the device to monitor the per-process memory footprint as well to help detect possible leaks and take configured action.

Memory can be exhausted when there is over scaling, for instance when you test a high scale on a device that does support the scale because of physical resource limitations. Memory can also be exhausted when there are temporary spikes for example when a new FIB object is added before the older FIB objects are deleted. These temporary spikes are usually transient and resolve after a while. Also, a memory leak in any one of the applications or even in the kernel can lead to memory exhaustion. So, it is necessary that you monitor memory usage across applications and the kernel.

Starting in Junos OS Release 23.1R1, you can configure the memory monitoring on the SRX Series, QFX Series, and EX Series devices to raise an alarm using the set system monitor memory system alarm command statement. The alarm is raised when the device is running low on memory.

The remaining statements are explained separately.


Enable system monitor alarm.

Required Privilege Level

system—To view this statement in the configuration.

system-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 20.1R1.

The alarm option is introduced in Junos OS Release 23.1R1.