First off, i ask you to discontinue whatever you do that causes the excessive formatting of your posts. Half of your text is various tags.

Paging space is used as a memory-extension in cases your running programs (want to) use more memory than you actually have. In times gone memory was very expensive and it was a good idea to make it look like a system has more memory available than it actually had. Today memory is cheap and one tries to avoid paging (swapping) at all costs.

Still it won't hurt to have some virtual memory available for extraordinary situations (diskspace is even cheaper than memory and hence wasting some of it matters even less), but in day-to-day operation the system should be able to do without using this swap space (paging space) at all costs.

Having said this, the following is a rule-of-thumb suggestion and in no way an exact analysis: I would start (in a system with a today typical memory size of 4-8GB) with 2-4GB of paging space for starters and watch carefully. If this paging space i used quite often you might want to increase the memory size, depending how often paging (that is: transfer of memory content to/from the paging space) really happens.

There are processes which "sleep" in memory for the whole day, get swapped out, start to work once a day and go back to sleep again. In this case you would see some paging space consumption, but not actual paging going on (save for the process waking up and getting swapped out again some while later). In such a case you might want to increase the paging space size to still have the 2-4GB in contention but leave the memory size as it is.

Monitoring the paging space

There are two distinct areas to watch when monitoring the paging space: the paging space consumption and the paging activity itself. Use

Code:

lsps -a

to watch the consumption in percents. Do this regularily, like every 10 minutes for starters, writing the results in a file. Once you have gained some knowledge about the system you can increase the sampling rate and only execute the command every hour or even only once or twice a day. Try the following as a basis for some monitoring script:

Code:

while : ; do
     lsps -a >> /path/to/lsps.monitor."$(date '+%Y%m%d')"
     sleep 600                 # take snapshot every 600sec=10minutes
done

Watching the actual paging activity is done similarily with "vmstat", but vmstat already works contiually, so you don't need any loop:

Code:

vmstat -Itw <interval_in_seconds> >>/path/to/vmstat.monitor."$(date '+%Y%m%d')"

Notice the part titled "page" and especially the "pi" (page in) and "po" (page out) columns. These should be mostly zero. Like with "lsps" start with some small sampling rate which you can increase once you know how the system performs in general.

You will want to read up about performance tuning and monitoring in general. There are some pretty informative threads here, off the top of my memory:

AIX 5.2 performance question
https://www.unix.com/aix/45180-hard-d...y-command.html
AIX : 0 pages swappes

... and probably a dozen more I'm not aware of.

I hope this helps.

bakunin