CPU Monitoring Is Disabled

[TMADOCTHOMAS]

I am working on a plan to upgrade from OnCommand Unified Manager 5.1 to 5.2R1.  On page 11 of the Release Notes, it says:

------------------------------------------

CPU monitoring is disabled by default on a newly installed DataFabric

Manager server. The CPU Usage (%) graph data is not available.

CPU monitoring is also disabled by default if you have upgraded to

OnCommand Unified Manager Core Package 5.2R1. The data in the CPU

Usage (%) graph expires over a period of time.

The historical data is available in the CPU Usage (%) graph in both the

OnCommand console and Operations Manager console until they reach

expiry.

------------------------------------------

Why would this be the case?  I am tracking a CPU issue on one of our filers now and need this information!  If I am reading correctly, I will not be able to view Processor information in Performance Manager after the upgrade.  Is this accurate?

[arunchak]

Hi,

Nothing is changed, only CPU monitoring is turned off by default. This was done intentionally because some of the customers wanted to run the filers at high CPU but were bugged with the warning events.

You just need to turn on the CPU mon by changing the option to Yes after upgrade for CPU monitoring to start working.

Thanks,

  Arun

[TMADOCTHOMAS]

Thanks Arun!  So I understand that CPU monitoring is now turned off by default, but I just want to verify that I can still use Performance Monitor to view data about the CPU.  The line "The CPU Usage (%) graph data is not available" is what concerned me.  That makes it sound like you can't chart CPU data anymore.  Is that accurate?

[arunchak]

AFAIK, once you enable to the CPU mon the CPU graph should start showing up.

Thanks,

Arun

[TMADOCTHOMAS]

Thanks Arun!  I have looked through the Ops Manager and Performance Advisor documents, and I cannot find how to manually enable CPU graph data.  Do you know what the command or menu option is?

[kryan · Accepted solution]

Greetings,

The public report for the bug where this change occurred states the option:

http://support.netapp.com/NOW/cgi-bin/bol?Type=Detail&Display=612203

CPU usage can be tracked through performance counters collected by Performance Advisor. Use the CPU Utilization graph in "Storage System Summary View" to track  the CPU utilization trend.

From 5.2 the CPU monitor is disabled by default, the monitor can be enabled by running following command:

# dfm option set cpumoninterval=

You should also find this information in the Release Notes starting with UM 5.2GA.

Thanks,

Kevin

[TMADOCTHOMAS]

Very helpful, thank you kryan!

[colin_graham]

This is true...

Since the newer versions of OnTap (8.1+) changed the way multiple CPUs cores are utilized, its somewhat broken the normal methods of seeing CPU utilization like DFM and sysstat.

Our 6210 with 8 cores per head can show being pegged at near 100% cpu in DFM for most the day, however in reality its between 30-40% - we get a few annoying "cpu too busy" messages a day.

To get a more accurate reading of total CPU usage you have to use the "sysstat -m" command from the controller's CLI and look at the Avg column:

Filer> sysstat -m 1

ANY  AVG  CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7

97%  43%   45%  41%  40%  41%  44%  45%  44%  44%

97%  41%   44%  38%  38%  40%  42%  41%  43%  42%

96%  40%   42%  37%  38%  40%  42%  42%  42%  41%

100%  59%   57%  56%  55%  56%  61%  62%  60%  61%

99%  48%   50%  47%  44%  47%  51%  50%  50%  49%

99%  55%   55%  52%  53%  51%  57%  56%  57%  56%

96%  37%   38%  35%  36%  36%  39%  37%  39%  38%

"Any" is the metric DFM uses to show CPU usage - and as you can see above, its not really representative of actual filer load.

Furthermore - background processes will consume cpu, but will back-off in response to client workloads. so without looking at other metrics like throughput and latency, CPU% is rather irrelevant.

[TMADOCTHOMAS]

Very helpful to know!  Thanks Colin.