50 DB2 Nuggets #18 : Tech Tip - Monitoring memory usage on AIX server

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I am quite sure that most of you are using 'svmon' utility with various option to monitor the memory utilisation on AIX box. The most useful option I found is 'P'. It quickly shows you the approximate memory consumption at process level:

$ svmon -G
               size       inuse        free         pin     virtual   mmode
memory      1572864     1454069      118795      639255     2062594     Ded
pg space    1572864      884144

               work        pers        clnt       other
pin          522668           0         907      115680
in use      1337170           8      116891

PageSize   PoolSize       inuse        pgsp         pin     virtual
s    4 KB         -      514725      135472      284935      500658
m   64 KB         -       58709       46792       22145       97621
$                       
                                        

How to read this output?

                                
- All values are in terms of number of pages. First section contains the number of pages with 4K pagesize. So 1572864 * 4K comes to 6GB.

- It shows that you have 6GB main (or real) memory allocated on this server and 6GB is configured as page swapping space.

- Main memory is almost 100% utilized (please see 'inuse' column). Thereafter your system will start using paging space. 

- The last section contains the detailed page level information.  Pagesize 's' stands for small page of size 4K. Pagesize 'm' stands for medium page of size 64K.    
                                                                        
This output displays memory utilisation at OS level. Please note that If the user is not a root user, the view will be limited to user's own processes.    

Now we will determine the memory consumers at process level:        

$ svmon -P | head -3 | tail -1;svmon -P | grep -p Pid | grep -v -- ^- | grep -v Pid | grep -v ^$
     Pid Command          Inuse      Pin     Pgsp  Virtual 64-bit Mthrd  16MB
33226854 svmon           274756     9760   474338   627309      Y     N     N
 8257536 sshd             20618    13748     1968    26084      N     N     N
14155982 sshd             20610    13748     1968    26076      N     N     N
29687824 ksh              20539    13748     1968    26082      N     N     N
24969310 ksh              20537    13748     1968    26080      N     N     N
33095906 grep             20396    13748     1968    26002      N     N     N
17694832 grep             20395    13748     1968    26001      N     N     N
24379472 grep             20395    13748     1968    26001      N     N     N
22806752 grep             20395    13748     1968    26001      N     N     N
                                                                        

Please look at the 'inuse' column in the output above. It shows the number of pages (of 4K size) in use by a particular process.        

HTH.

Thank you,

Yogesh.