We have encountered a similar situation here. AIX 5.2, Qdx 5.3r2. On one of our engines the host server runs amok several times a week. Usually, it will stop after a ten minute spasm, but yesterday it ran full tilt for a couple of hours before I bounced it. The short spasms are just long enough to trigger our CPU alerts, and our operators have started to ignore them, becuase it clears itself up after a few minutes.
Is there anything that I should be looking at as a potential cause for this behaviour?