SRX routing engine low memory

If your SRX device has 1GB memory and you are using IDP and/or Antivirus then you may play with the memory allocation a bit with a new feature introduced in 11.4. As I always do, I will show it by an example;

Here is my srx100 memory utilization;

If your control memory utilization is above 95%, it may be better for you to do this adjustment. Let’s increase control plane memory by 64MB.

As you can see this change requires a reboot. Now look at the control plane memory after this change;

Enjoy your extra 64MB 🙂

2 thoughts on “SRX routing engine low memory

  1. Joe

    Very nice tweak I will need to remember. This is from my SRX240H @ idle:
    Total memory 1024 MB Max 696 MB used ( 68 percent)
    Control plane memory 560 MB Max 386 MB used ( 69 percent)
    Data plane memory 464 MB Max 311 MB used ( 67 percent)

    I am using IDP and AV on my SRX and wanted to know what sort of port density or traffic load was required to raise the RAM usage to 95%? Was it easy for you to overload the SRX once you had the RAM usage that high or did JunOS pretty much take it and stay stable?

    1. rtoodtoo Post author

      At around %90 percent control plane memory, I can say that it is working stable but both AV and IDP in an active network may cause extra utilization depending on the level of AV compression levels, IDP policies i.e options you enable.
      %95 figure as far as I can remember is a level that should be considered high according to Juniper KBs but don’t recall where I read it exactly. If you can share your experience from your active network, that would be very good as well:)


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