BIG-IP uses SWAP memory though TMM memory is free?

How are you determining swap is used. From within the HMS? If so, that swap is used by the HMS, not TMM.

Perhaps you're referring to the swap memory of the management OS? The TMM and management are separate.

/Patrik

Hi Patrik,

Here is the result of the free command, executed in QKview > Commands.

             total          used          free       buffers        cached
Mem:        4061476       3990056         71420        384344        633064
-/+ buffers/cache:        2972648       1088828
Swap:       1048568         20192       1028376

Here we can see that swap was being used. Any clue?

Thanks, Darshan

That output relates to the HMS, the management OS, not TMM.

Oh I see! But what is HMS? And how did you confirm it is Management OS and not TMM?

Thanks, Darshan

So is it normal where HMS uses system Swap memory? Or in any specific case this happens?

Take a look at the HMS book I have here (the PDF) and hopefully all will become clear: https://www.wuala.com/sjiveson/Public/?key=BlKE7DHaCzCL

I have diagnosed the QKview and found that TMM memory is freely available, however still BIG-IP used SWAP memory.

i am not memory expert but i think that is normal.

Does it indicate any memory issue?

i do not think so.

Also understand that a BIG-IP is always running TWO concurrent operating systems. The Traffic Management OS (TMOS), often referred to as the "data plane", is where traffic management happens, iRules, and client-sever data flow. Then you have the "HMS" as it's being referred to here. It's a Linux-based OS used for bootstrapping TMOS and for generic "management plane" functions - cron jobs, external monitors, the Apache/mod_ssl/PAM/MCP services used by the management GUI, the iControl interface, and the management and provisioning hooks into TMOS. No client-server data passes through the management plane. When the system boots, TMOS reserves the lion's share of total system memory, leaving a very small chunk for the management subsystem. If you use one of the typical Linux-based tools to look at memory and processes (i.e. ps, top), you're going to see what the management plane sees. You have to look from within TMOS to see what's being used inside the reserved memory space.

It is also the nature of Linux systems to proactively age out memory to the swap partition/file to make actual swap operations faster. So even though large amounts of memory are free and the system is enduring no memory pressure, swap continues to be in use but not for actual swap operations.