AIX - How to monitor memory usage

In AIX, ps command can be used to monitor status of processes. It will display information such as CPU usage, memory usage and etc of processes. To monitor memory usage of processes, RSS and %MEM column need to be refer to as they are the parameters related to memory. Below is a quick explanation on what RSS and %MEM referred to.

RSS - The amount of RAM used for the text and data segments per process. PID 15256 is using 2888k. This is the real memory being used by the process.

%MEM - The actual amount of the RSS / Total RAM. Processes using large percentages of memory should be examined further, although remember that database and HPC applications can use the entire memory block as normal and could be ignored. On a more general purpose system, any single process can use a lot of memory.


Question : How to monitor memory [%MEM] in AIX?
Answer : ps command can be used to report a snapshot of the current processes in AIX. Use option aux and sort based on the column to get the top usage based on the parameter you need. If you need to get %MEM then you will need to sort column 4.
Example :

[root@server ~]# while true;do echo `ps aux |head -1`;ps aux |sort -nrk 4| head -10;sleep 2;clear;done

Note : Above command will output top 10 processes with highest %MEM in an interval of 2 seconds. Press "Crtl C" to exit the while loop.


Question : How to show overview of memory usage in AIX?
Answer : svmon command with option "G" can be used to show overview of memory usage in AIX. To continuos output in specific interval, option "i" followed by interval and numintervals values are needed.
Example :

root@server # svmon -G size inuse free pin virtual mmode memory 131072 126083 4989 88483 201381 Ded pg space 262144 76328 work pers clnt other pin 81529 0 0 6954 in use 120504 0 5579 PageSize PoolSize inuse pgsp pin virtual s 4 KB - 88371 65160 68899 142389 m 64 KB - 2357 698 1224 3687

Note : Above command will output overview of memory usage in interval of 3 seconds for 3 times. You need to calculate the memory size by multiplying memory size output with 4kb.


Question : How to monitor memory usage of a specific process in AIX?
Answer : svmon command with option "P" followed by PID can be used to specific which process to monitor.
Example :

[root@server ~]# svmon -P <PID>