How to deal with Paging space in AIX?

 
How to deal with Paging space in AIX?
 
 
The general recommendation is that the sum of the sizes of the paging spaces should be equal
to at least twice the size of the real memory of the machine, up to a memory size of 256 MB (512 MB of paging space).
 
Note: For memories larger than 256 MB, the following is recommended:
 
total paging space = 512 MB + (memory size - 256 MB) * 1.25
 
Run below command for paging space utilization.
 
$] lsps -s
 
Total Paging Space        Percent Used
52608MB                    90%
 
Solution: Minimum 180 GB paging space required.
 
 
Use this command to see the characteristics of a paging space:
# lsps -a
 
$ svmon -P -O summary=basic,unit=MB
Unit: MB
 
-------------------------------------------------------------------------------
     Pid Command          Inuse      Pin     Pgsp  Virtual
47318066 oracle        32519.96     50.2 15285.19 33364.55
60293760 oracle        32458.31     50.2 15285.19 33302.93
44565378 oracle        32443.12     50.2 15285.19 33287.74
51315730 oracle        32442.37     50.2 15285.19 33286.99
28181816 oracle        32442.18     50.2 15285.19 33286.80
 2623044 oracle        32441.56     50.2 15285.19 33286.18
24904292 oracle        32440.68     50.2 15285.19 33285.30
 
 
 
 
$ ps -ef | egrep "PPID|${pid}" | grep -v grep ; svmon -P $pid | head -10
 
-------------------------------------------------------------------------------
     Pid Command          Inuse      Pin     Pgsp  Virtual 64-bit Mthrd  16MB
47318066 oracle         8325109    12884  3913009  8541325      Y     N     N
 
     PageSize                Inuse        Pin       Pgsp    Virtual
     s    4 KB                5045          4        449       4845
     m   64 KB              520004        805     244535     533530
     L   16 MB                   0          0          0          0
     S   16 GB                   0          0          0          0
 
 
 
 
Paging Space utilization on SAMIK-RAC1 AIX Server:
*****************************************************************
 
The paging space on SAMIK-RAC1 is mainly still used by the Oracle database.
There are still some Oracle processes running since a long time.
It has been assumed that the pages in paging space are for shared memory segments
which are used by all Oracle processes and as long as not all Oracle processes are stopped together,
the paging space will not get freed up.
 
As an example please find below the analysis of two processes from user oracle,
one was started in September last year and one was started today:
 
root@SAMIK-RAC1[/root]for pid in 65405480 15270852 ; do ps -ef | egrep "PPID|${pid}" | grep -v grep ; svmon -P $pid | head -10 ; done
 
     UID      PID     PPID   C    STIME    TTY  TIME CMD
  oracle 65405480        1   0 04:30:31      -  0:00 oracleORCL (LOCAL=NO)
 
-------------------------------------------------------------------------------
     Pid Command          Inuse      Pin     Pgsp  Virtual 64-bit Mthrd  16MB
65405480 oracle         8301087    12836  3913009  8517341      Y     N     N
 
     PageSize                Inuse        Pin       Pgsp    Virtual
     s    4 KB                5039          4        449       4845
     m   64 KB              518503        802     244535     532031
     L   16 MB                   0          0          0          0
     S   16 GB                   0          0          0          0
##############################################################################################
 
     UID      PID     PPID   C    STIME    TTY  TIME CMD
  oracle 15270852        1   0   Sep 05      -  1:30 ora_w00g_ORCL
 
-------------------------------------------------------------------------------
     Pid Command          Inuse      Pin     Pgsp  Virtual 64-bit Mthrd  16MB
15270852 oracle         8298947    12836  3915261  8517341      Y     N     N
 
     PageSize                Inuse        Pin       Pgsp    Virtual
     s    4 KB                3667          4       1821       4845
     m   64 KB              518455        802     244590     532031
     L   16 MB                   0          0          0          0
     S   16 GB                   0          0          0          0
##############################################################################################
 
 
Both processes are using almost 15 GB of paging space
 
(e.g. 244590 * 64 GB pages and 1821 * 4 KB pages for process with PID 15270852)
 
The process with PID 15270852 (ora_w00g_ORCL) is used for DB or any helper services,
but once all those kind of processes are stopped together with the DB the paging space utilization should go down again.
If not a reboot would be required then.