vxiod had high cpu util but gbl cpu util is low?

[Todd Larchuk]

I am using GlancePlus version c.02.65.00 to collect CPU utilization data and every now and then a process "vxiod" shows up with 100% cpu utilization but the global cpu utilization is only at 3%. What's going on here? The man page for vxiod says it's a Veritas Volume Manager demon that won't show up on ps. What's that all about?

Thanks in advance.

[Jeff Schussele]

Hi Todd,

Is it a safe assumption that you're using Veritas Volumes?
If so according to the vxiod man page, you may wish to start more than one vxiod daemon...

\Quote

The vxiod utility starts, stops, or reports on Volume Manager I/O daemons. An I/O daemon provides a process context for performing Volume Manager I/O. Volume Manager I/O daemons are not required for correct operation, but not having I/O daemons can adversely affect system performance.
When invoked with no arguments, vxiod prints the current number of volume I/O daemons on the standard output.

The number of daemons to create for general I/O handling is dependent on system load and usage. If volume recovery seems to proceed slower at times, it may be worthwhile to create more daemons.

Each I/O daemon starts in the background and creates an asynchronously-running process, which detaches itself from the controlling terminal and becomes a volume I/O daemon. The vxiod utility does not wait for these processes to complete.

\Endquote

Run vxiod w/o any arguments & it will report the number of daemons currently running.

And to your question on whether ps can see them - here's another snippet from the man pg

\Quote

Volume Manager I/O daemons cannot be killed directly through the use of signals.
The number of Volume Manager I/O daemons currently running can only be determined by running vxiod; I/O daemons do not appear in the list of processes produced by the ps command.

\Endquote.

So I'd say that belief is correct. Only vxiod itself can report on it's usage.

Rgds,
Jeff

[Todd Larchuk]

As far as I know, we're not using Veritas Volumes.

What I don't understand is how vxiod, or any process, can be measured by GlancePlus as using 100% proc_cpu_util while at the same time the gbl_cpu_util is near zero?