Diagnosing a Bad Disk Layout

A non-optimal physical disk layout can cause one single physical disk to become the bottleneck of a SAN. To verify that the I/Os are well-balanced across all physical disks you can check the Read Byte Rate and Write Byte Rate parameters of each physical disk and make sure they have similar average values.

Verify Physical Disks Workload Distribution

1.	In the console, double-click the Write Byte Rate parameter of the first disk for which you need to compare the activity. A graph is automatically displayed in the graph pane.

TREE_Write_Byte_Rate

Selecting Write Data Rate Parameters

2.	Select the Write Byte Rate parameter of the second disk and drag it from the tree view of the Operator tab to the graph. The second parameter is automatically added to the first one to facilitate the comparison. Repeat this operation for any other disk.

GRAPH_Write_Byte_Rate

Comparing Several Physical Disks' Write Byte Rate Parameters