Monitoring Logical and Physical Disks

Applies To: Operations Manager 2007, System Center 2012 - Operations Manager, System Center 2012 R2 Operations Manager, System Center 2012 SP1 - Operations Manager, Windows Server 2012, Windows Server 2012 R2

The same set of monitors apply to Logical Disks, Cluster Shared Volumes, and Clustered Disks.

Evaluate the default settings for the following parameters and compare them against your business needs. If your monitoring strategy could benefit from a change in these values, use overrides to make the necessary changes. For more information about overrides, see the "Overrides in Operations Manager 2007" topic in Operations Manager 2007 Help

Monitoring Logical Disk Free Space using the Logical Disk Free Space monitor

The default health state thresholds for the Logical Disk Free Space monitor are different for system and nonsystem logical disk volumes. Error and Warning health states are based on both percentage of free space and on an absolute value, designated in megabytes (MB), of free space, as shown in the following sections.

System Partition

Nonsystem Partition

By designing this monitor to evaluate both percentage free and MB free, the monitor works equally well for disks regardless of their storage capacity. This monitor does not alert on warning state, only on error state.

Monitoring Logical Disk Free Space using the Disk Free Space (%) Low and Disk Free Space (MB) Low monitors

The thresholds used in these monitors are exactly the same as the ones used for the Disk Free Space Monitor.

One reason for using these monitors is when you want to alert separately on available MB and %free space. You should then disable the Logical Disk Free Space monitor.

These monitors do not alert on a warning state, only on error state.

Monitoring Logical and Physical Disk Performance

The following monitors can be used to assess disk performance. By default, Average Disk Seconds Per Transfer is enabled. Average Disk Seconds Per Read and Average Disk Seconds Per Write are not enabled by default. For more information about enabling these two monitors, see the "How to Override a Monitor" topic in Operations Manager 2007 Help.

Average Disk Seconds Per Transfer

Average Disk Seconds Per Transfer monitors the time, in seconds, of the disk transfer. The default threshold value is .04. This monitor collects fifteen samples to compute the threshold. The threshold is met when the value of all fifteen consecutive samples is greater than .04. The health state is considered Healthy when it is below the threshold value and Critical when it is above the threshold. We recommend leaving the threshold at its default value of .04 seconds for an average disk transfer, which is considered acceptable performance.

Average Disk Seconds Per Read and Write

Average Disk Seconds Per Read is the average time, in seconds, to read data from the disk. Average Disk Seconds Per Write is the average time, in seconds, to write data to the disk. The threshold for both these monitors is .04 seconds and a sample is taken every minute. These monitors collect fifteen samples to compute the threshold. The threshold is met when the values of fifteen consecutive samples are greater than .04.