Difference between top and vmstat

[O'Prometheus]

Hi.. I'm having an issue with a Centos 5.6 server & noticed that top reports 0.0% cpu idle time. (user and system typically split 80/20 but varying)

The actual issue is intermittent network disconnects that may (arguably) be caused by a spinning cpu. However, vmstat reports 99% idle time (much as I would normally expect it).

I'm planning a reboot to see if that can help (it hasn't been rebooted in a year and a half) but I'm intrigued what might be causing the discrepancy.

Any thoughts welcome.

[gerald_clark]

So you have not applied any security/bug fixes for a year and a half.
Do a yum update, reboot, and see if the issue still exists.

[TrevorH]

You need to update. Badly. 5.6 was released over 4 years ago and there have been numerous security related patches since then. Some of them serious. If you update then you'll get a 4 year newer kernel and many bugs have been fixed in that too.

[O'Prometheus]

Alas update isn't an option. Its a regulated system

Its also isolated, so security is mitigated (a little, at least).

[gerald_clark]

Well, if you can't do any updates, you will have to live with it the way it is.

[O'Prometheus]

Well, if you can't do any updates, you will have to live with it the way it is.

I guess that much I'm comfortable with, but I like to know what it is I'm living with, if there is a difference between top and vmstat, which is authoritative?

The presenting complaint is something that may well have been patched, too, and I'll have to live with that, too.