What would cause a system wide increase in cpu utilization

[Vball23]

RX8620
16 cpu
128GB memory
Connected to IBM DS8100 via SVC san
Connected to EVA via san

50 oracle databases

Starting a week ago, cpu utilization has increased noticeably for every process and I/O wait has increased as well.

No system changes have been made for quite some time.

gzip processes that normally take 1 hour have increased to 3 hours

System was up for 125 days. I shut down all databases and rebooted the server and all is well I/O and cpu now since Saturday.

Any ideas or quesses what could affect these resources system-wide?

[Christian Tremblay]

You should use either top or glance to check what process(es) are eating up all the cpu.

Chris

[Sandman!]

Any log of what changes were made to the environment? What about historical metrics so that you can compare what changed and by how much?

[A. Clay Stephenson]

Sadly, when you rebooted, you threw away the very data that would have made it possible to answer your question. You really should have determined the cause of the problem before the reboot else it is likely to reoccur. As a guess (all I am left with as a diagnostic tool is "The Force"), is that you have an application with a memory leak and eventually you were forced into a situation with lots of paging and context switches. You should monitor processes that are growing in memory size over time.