--On Tuesday, December 10, 2013 08:18:09 AM -0800 John R Pierce pierce@hogranch.com wrote:
during idle time, dirty pages will be written to swap so they can then be discarded if needed. ignore it, it means nothing
Agreed. If you want to see if paging is actually an issue, run "vmstat -5" and ignore the first line of output. If, over time, you're seeing consistently high values for the si and so columns, then you have something to investigate. If they're usually low or zero, then ignore your swap usage.
Same thing goes for the "free" values in top and vmstat; having low free memory counts in a long running kernel is normal and can be ignored. (Too many people, especially coming from the windows world, get wrapped around the handle about this.)
If you want to maintain a historical record of memory and other performance indicators that you can use for investigative purposes after the fact, see the man page for sar(1).
Devin