AIX

hahahhaa... i hear ya, bud. the problem nowadays is that from the perspective of "sizing", you're at the mercy of your application vendor.

Negm, be aware that there is a fundamental difference between AIX versions prior to 4.3.3 ML10 (aka "AIX 4.4") and after this version. Before 4.3.3 ML10 AIX had an "early swap allocation strategy", that means that as a program got started the page necessary to swap it out was allocated even if it was held in memory. That meant that usage rates of 60% or more weren't that troublesome at all because "swapspace used" was meaning "swapspace marked in use for eventually swapping out something now in memory". Only vmtstat could tell you the real state of the machine.

With AIX 4.3.3 ML10 that changed to a "late swap allocation strategy", like the othere major UNIX vendors employed. Swapspace is now allocated only as it is (really) needed, meaning, when processes are being swapped out of memory.

In short: without knowing which AIX version you are talking of it is simply impossible to find out what is going on on your machine.

bakunin