page-out while having lots of free memory, HP-UX 11.31

[hpuxbmo]

Hi experts,

we noticed this from OEM(Oracle Enterprise Manager) first. I also extracted MeasureWare data which has free memory and page-out data for one week.  You can see from 13:10 to 14:10 on Nov.15th, some consistent page-out happened while there were more than 25GB free memory (about 55% memory utilization).  Could you help explain why this happened and should this be a concern to us?

Thanks.

OVPA Export 11/18/15 07:11 Logfile: /var/opt/perf/datafiles/logglob SCOPE/UX 11.14.014(4)
| |Active| | Phys | Phys | Free |Memory| User | | Pg Out | Pg Out |
Date | Time | CPUs |CPU % | IO Rt | IOs | Mem | % |Mem % |Swap %| KB | KB Rt |

11/15/2015|12:30:00| 6| 7.83| 48.2| 14460| 26115| 54.50| 29.02| 29.00| 0| 0.0|
11/15/2015|12:35:00| 6| 7.45| 33.5| 10050| 26060| 54.60| 29.11| 30.00| 0| 0.0|
11/15/2015|12:40:00| 6| 9.82| 24.8| 7459| 26035| 54.64| 29.16| 30.00| 0| 0.0|
11/15/2015|12:45:00| 6| 7.51| 42.4| 12724| 26011| 54.68| 29.14| 30.00| 0| 0.0|
11/15/2015|12:50:00| 6| 6.78| 28.2| 8460| 26017| 54.67| 29.14| 30.00| 0| 0.0|
11/15/2015|12:55:00| 6| 17.20| 30.1| 9030| 25978| 54.74| 29.20| 30.00| 0| 0.0|
11/15/2015|13:00:00| 6| 34.19| 460.9| 138131| 26020| 54.67| 29.15| 30.00| 0| 0.0|
11/15/2015|13:05:00| 6| 24.31| 288.2| 86402| 25731| 55.17| 29.15| 30.00| 0| 0.0|
11/15/2015|13:10:00| 6| 25.61| 415.8| 124947| 25736| 55.16| 29.14| 30.00| 480| 1.6|
11/15/2015|13:15:00| 6| 26.61| 506.9| 152070| 25766| 55.11| 29.10| 30.00| 9660| 32.2|
11/15/2015|13:20:00| 6| 26.08| 513.5| 154358| 25793| 55.06| 29.12| 30.00| 14038| 46.7|
11/15/2015|13:25:00| 6| 24.28| 421.7| 126467| 25799| 55.05| 29.08| 30.00| 9716| 32.4|
11/15/2015|13:30:00| 6| 25.08| 368.3| 110084| 25821| 55.01| 29.04| 30.00| 28963| 96.9|
11/15/2015|13:35:00| 6| 24.75| 428.2| 128502| 25759| 55.12| 29.13| 30.00| 13714| 45.7|
11/15/2015|13:40:00| 6| 26.82| 286.8| 86269| 25732| 55.17| 29.17| 30.00| 12001| 39.9|
11/15/2015|13:45:00| 6| 23.87| 542.8| 162948| 25797| 55.05| 29.11| 30.00| 27798| 92.6|
11/15/2015|13:50:00| 6| 21.57| 237.8| 71268| 25783| 55.08| 29.13| 30.00| 14265| 47.6|
11/15/2015|13:55:00| 6| 21.50| 238.6| 71723| 25825| 55.01| 29.06| 30.00| 8537| 28.4|
11/15/2015|14:00:00| 6| 32.15| 267.7| 80042| 25821| 55.01| 29.05| 30.00| 33368| 111.6|
11/15/2015|14:05:00| 6| 34.44| 269.5| 80930| 25769| 55.10| 29.13| 30.00| 13213| 44.0|
11/15/2015|14:10:00| 6| 13.97| 343.3| 103195| 27392| 52.28| 29.10| 30.00| 3306| 11.0|
11/15/2015|14:15:00| 6| 8.82| 64.3| 19296| 27369| 52.32| 29.12| 30.00| 0| 0.0|
11/15/2015|14:20:00| 6| 6.79| 39.1| 11730| 27374| 52.31| 29.11| 30.00| 0| 0.0|
11/15/2015|14:25:00| 6| 6.75| 30.5| 9150| 27403| 52.26| 29.06| 30.00| 0| 0.0|
11/15/2015|14:30:00| 6| 7.14| 45.8| 13744| 27419| 52.23| 29.02| 30.00| 0| 0.0|
11/15/2015|14:35:00| 6| 7.44| 36.4| 10894| 27373| 52.31| 29.10| 30.00| 0| 0.0|

[Bill Hassell]

Page out rates cover two very different conditions: moving pages of memory to the swap area and memory mapped files. Since the swap usage did not seem to change during that period, the page outs are likely memory based file activity. Nothing to be concerned about.