Diagnosing a Bad Physical Disk Layout

A non-optimal physical disk layout can cause an array of physical disks to become the bottleneck of a SAN. To verify that the I/Os are well-balanced across all arrays and ranks you can check the ReadByteRate and WriteByteRate parameters as well as the ReadResponseTime and WriteResponseTime of each rank and make sure they have similar average values.

Verifying the activity on physical disks

1.In the console, right-click the KM icon > KM Commands > Reporting > Volumes Activity

2.Select the volume read/write bytes traffic parameter

KMCmd_Report_Volume

Configuring the Report Settings

3.Select the report range and interval

4.Press the Volumes Selection button to select the specific volume(s) you wish to include in the report. By default all the monitored volumes are included in the report.

The Volume selection option is only available when at least two volumes are monitored.

Verifying physical disks response time

1.In the console, double-click the DiskReadResponseTime parameter of the volume you are interested in. A graph is automatically displayed in the graph pane.

2.Drag the DiskWriteResponseTime parameter of the same volume in the graph.

TREE_Read_WriteResponseTime

Selecting Graph's Parameters