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Hame_35062's avatar
Icon for Nimbostratus rankNimbostratus
Mar 15, 2011

IS it ok to have F5 memory usage high


In my F5 load balancer ( BIG-IP LTM 1600) memory usage high. I have attached a snap shot also. Pls advice DO i need an upgrade or is this normal. My CPU and RAM utilisation seems ok.




System Memory


Host Total 3.4G


Host Used 3.3G




TMM Total 2.7G


TMM Used 43.4M




Pls advice on this.






4 Replies

  • I've had this happen on a couple units as well and was told it was fine. I'd recommend creating a support case though as I forgot why F5 said it wasn't an issue. I recall them saying my system would automatically clear out memory as it needed it though. What version are you on?
  • nathe's avatar
    Icon for Cirrocumulus rankCirrocumulus



    I think this may help



    "...the Host used memory is reported higher than in BIG-IP versions prior to 9.4.7 and 10.0.0. Subtracting the TMM total memory from the Host memory allows you to calculate the actual amount of memory used by the Host system"



  • Thanks Nathan and Miller.



    My LB is BIG-IP LTM 1600, version 9.4.8. Build 355.0 final.



    As you say this is noramal; I'll dig on it.


    CAn anyone tell me what is the difference between Host and TMM memory.





  • CAn anyone tell me what is the difference between Host and TMM memory.



    Host memory is memory being used by the Linux Host, and TMM memory is memory being used by the Traffic Management Kernel. See Simple! ;)



    To really understand this you need to understand how F5 has built their product, and elegantly so I might add..



    F5 is the product leader in the ADC/Load Balancing arena for a reason.. They didn't throw their Traffic Management logic on top of an operating system like some other competitors which will remain nameless ;).... They build their own operating system for Traffic Management and put it beside the managment OS.. enter TMOS , Traffic Management Operating System



    TMOS is totally autonomous from the Linux kernel, Linux does not participate in the Traffic Management flow at all.. TMOS has it's own dedicated CPU, memory and bus.



    You see, an operating system like Linux is a great general purpose OS for scheduling tasks, scripting, etc.. It schedules CPU time, therefore, It's not really suited for high speed Traffic Management operations.. TMOS is a REAL TIME OS, meaning it does away with the overhead of the CPU scheduler, it performs the necessary operations as they come, which equates to a very efficient OS for traffic management...



    For more general purpose info on TMOS see the White Paper:





    For a whole boat load of reading fun ;), see F5's complete White Paper list here: