Solution : https://service.sap.com/sap/support/notes/973227 (SAP Service marketplace login required)
Summary :
The SAP Note addresses issues with high paging rates and low free memory values in AIX systems due to inefficient Virtual Memory Management settings, especially impacting SAP systems on DB servers. The note suggests modifying several VMM parameters (minperm%, maxperm%, maxclient%, lru_file_repage, strict_maxclient, strict_maxperm, minfree, maxfree) to optimize memory handling and minimize unnecessary paging. The updated tunables primarily aim to ensure computational memory pages are prioritized over file pages, reducing redundant data buffering and improving system performance. Recommendations require specific AIX maintenance levels for effective implementation. Users can modify settings via the smit fastpath "TunVmo" or command line.
Key words :
minperm% = 3maxperm% = 90maxclient% = 90lru_file_repage = 0strict_maxclient = 1strict_maxperm = 0minfree = 960maxfree = 1088you, prerequisites aix virtual memory management, minfree = 960maxfree = 1088these settings, free list dropping close, steal working segments leading, page-replacement algorithm runs, free list reaches maxfree, vmm page replacement tunables, symptom high paging rates, current default threshold settings
Related Notes :
| 1508983 | Long running Garbage Collection cycles |
| 921196 | AIX Memory Tuning Recommendations >5.2 |
| 856848 | AIX Extended Memory Disclaiming |
| 793113 | FAQ: Oracle I/O configuration |
| 78498 | High paging rate on AIX servers, in particular DB servers |