Development team

One of the subtle changes in OpsMgr 2012 was a re-write of the agent CPU utilization script. This new script more accurately calculates CPU utilization from the agent. This new script removes the CPU overestimation which was seen in the previous version the non-relevant alerts that had occurred as a result of the older version of the script. This change has bearing especially when performing a multi-homed migration. I am working with a client where we are multi-home migrating from OpsMgr 2007 R2 to OpsMgr 2012 and we started seeing agent CPU utilization alerts from the Operations Manager 2007 R2 environment.

When we investigated further what we found was that the actual processor utilization (shown by both task manager and the Operations Manager processor counter) was much lower than what was being reported by the Operations Manager Agent CPU utilization performance counter.

In the graphic below, the Red counters are agent CPU impact and the Yellow counters are the actual processor utilization on the system. This is non-logical as the actual impact on the CPU should not be higher than the CPU utilization.

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Figure 1: OpsMgr 2007 R2 Red indicates agent overhead, Yellow indicates processor utilization.

Investigating the same system in the OpsMgr 2012 environment showed a more logical breakdown shown below. As with the graphic above the Red counters are agent CPU impact and the Yellow counters are the actual processor utilization on the system. This appears to more closely match the reality of the situation where the utilization which occurred as a result of monitoring was less than the actual utilization occurring on the server.

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Figure 2: OpsMgr 2012 Red indicates agent overhead, Yellow indicates processor utilization.

Based upon the change in the script and how it behaves in OpsMgr 2007 R2 versus how it behaves in OpsMgr 2012 we ended up disabling the alerts from the OpsMgr R2 agent utilization scripts.

Summary: In a multi-homed Operations Manager 2007 R2 / 2012 migration if you are receiving agent CPU utilization alerts from the 2007 R2 but not from the 2012 environment it is most likely ok to either override or disable the OpsMgr 2007 R2 agent utilization script.