I'm using ZCS Community 4.5.10 and every couple of days (2-4 days) the CPU load will skyrocket causing the system to become unresponsive. When this happens, I ran top and noticed that the %wa often stay at 99% or a little bit lower. I'm thinking maybe this is because of Java (seeing that it takes the highest amount of resource) or something in the crontab job. As a reference, I've attached a screenshot of top and catalina.out with this post.
The system serves 15-20 mailboxes, it runs on Ubuntu6, and it is virtualized with Microsoft Virtual Server 2005 R2. Other guest systems (Windows) experience no similar symptoms and they are very stable. Because of that, I think we can safely rule out the possibility of a faulty hard disk. Any idea why this is happening?