Page Faults and Memory Usage

[FRED Dennison]

I have a (possibly dumb) query about Page Faults.

Is there guidelines on appropriate ratios of Page Faults to Page Ins? (2:1 presently) I have very few Page Outs.

I am interested in any tuning measures to reducing Page Faults - can we tune the TLB Buffer? I am only seeing 80-85% total memory usage, which indicates to me that memory is available but not being used.

LOTSFREE, DESFREE & MINFREE are not set, so I assume must be default. As free memory is 15-20%, LOTSFREE is not being reached (1/16th or 6.25%).

Buffer Cache is 25% (at max_dbc_pct value), with a small %wio and 90%+ in buffers (sar -u, sar -b).

Any input greatly appreciated. Thanks, FRED

[John Bolene]

Sounds to me that you are doing good.

You will always have page faults and page-ins when the system finds that something is not in memory that it needs.

Everything is good if you do not have many page-outs. Page-outs will occur if memory gets tight and if a job does a malloc and memory space is not available contiguously. After this page-out is done, page-ins will be needed when the paged-out process gets control.

Extra memory will be used for file buffering (caching) and will normally take most of the rest of what you have if a lot of file I/O is being done.

If this does not answer the question, more detail is needed about what you expected to happen.