AIX shows 100% used physical memory

[Former Member]

Hi All,

can anyone help with this scenario please. We ahve been  facing it everyday now in QA PI system which runs in AIX.

I coudnt see much in top process as well . See attachment for both of them.

Both database and application are hosted on the same server. Can anyone help me to as to how to find why this is happening.

Regards,

Vishwanath B

[Former Member · Accepted solution]

Hi Vishwanath,

Maybe the following links will be useful for your scenario

Profile Parameters of Memory Management - SAP Memory Management (BC-CST-MM) - SAP Library

Extended Memory is 100 % in use on AIX | SCN

Thanks

[former_member184544]

Hi Vishwanath ,

AIX traditonally allocates all free memory to OS file cache and takes it back when needed .There are several SAP Notes on this topic as well . Also there are AIX parameters which you can set to control this behaviour of AIX all this is detailed in SAP notes available on market place.y

Also i see you have more than 50% paging which also means your physical memory has exhausted and the above scenario of file cache usage is not the case.

I would do the following :

-> Check Java VM settings ie the heap size and the no of processes you have.

-> Do you have frequent FULL Garbage Collection occuring ?

Respond to these questions and i will be able to help

[Former Member]

Hello Nagarajan,

Thanks a lot for ur reply

i will get back to you with the details tomorrow

BR,

Vishwanath B

[Former Member]

Hello Vishwanath,

Opening point, please provide info on:

1. Version of AIX

2. DB you are running and post memory allocated to the DB

3. Version of PI you are running

4. Version of kernel you are running

We can see that your using 54% of your page are so I'd imagine you're seeing heavy paging peaks on the system.

If you are on a dual-stack PI, please post a screen shot of tx ST02.

KR,

Amerjit

[Former Member]

Hi Vishwanath,

Question 1 - is the 100% memory usage causing you an issue?  If not, do not worry about it.  AIX will use the memory it has spare for file system cache, etc., as your screenshot shows. 

Question 2:  is this Java only or ABAP + Java?  A Java system is likely to need up to 16GB RAM on it's own, without considering the Oracle buffers.  How many java processes are started?  They can easily consume 2Gb RAM each.

Q3:  How much memory is allocated to Oracle?

Check out the 3 things above, but you may simply need to add more RAM if there is a problem.

Regards,

Graham