Server is running Centos 5.4 (final) with 8Gb ram 2 x Core udo 2.8Ghz software raid configured.
Every 1 hour the loading spikes from 0.16 up to 4.04 and locks up everything for around 5-65 minutes. There is no noticable change in CPU or memory just the increase in loading. "top" does not reveal which app is causing the problem.
Any ideas on how to identify the culprit?