cancel
Showing results for 
Search instead for 
Did you mean: 

High page out rate in 11.31

SOLVED
Go to solution
ESCDEMO
Occasional Advisor

High page out rate in 11.31

Hi,

I have installed the 11.31 on BL890C server,and filecache_max is only 3% of total 64GB memory. But I found the page out rate is over 10%, although the memory utilization is around 50%. Could anyone explain why the page out rate is high? Thanks!
5 REPLIES
Dennis Handly
Acclaimed Contributor

Re: High page out rate in 11.31

The high PO rate seems to only occur during certain times. Do you know what's going on then?
These could be large mmapped files being flushed. Or large shared memory segments.
ESCDEMO
Occasional Advisor

Re: High page out rate in 11.31

Hi,

Thanks for yur reply! But I had never seen the page out rate on 11.23 using OVPM while free memory is large.
Don Morris_1
Honored Contributor
Solution

Re: High page out rate in 11.31

Buffer cache flushes on v2 are not counted as pageouts. On v3, however - since the file and buffer caches are unified, the same mechanism flushes that cache -- which means that file cache management will generate pageouts. Assuming that your 3% file cache results in the contents of the cache being pushed out due to the referenced file space being larger, that could easily account for the difference in behavior.
Ismail Azad
Esteemed Contributor

Re: High page out rate in 11.31

Hi,

What don is talking about is the concept of something called as UFC or the unified file cache which takes away the concept of storing file access data and memory mapped file data being implemented as seperate caches which are controlled by different system calls to provide better coherency .Unified file cache is a feature of 11.31. Do assign points for folks who have helped you if you find the answer useful.

Regards
Ismail Azad
Read, read and read... Then read again until you read "between the lines".....
ESCDEMO
Occasional Advisor

Re: High page out rate in 11.31

Thanks for your explanation!