Detecting Unbalanced Workload Distribution on Controllers

A storage controller manages the flow of information between the server and the data. Disk arrays typically come with at least two storage processors to prevent fail overs and to enable load balancing. For best levels of performance, the workload needs to be properly balanced between two, or more, controllers.

Compare the controller throughput

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

TREE_Ctl_TransferByteRate

Selecting Controllers's Parameters

2.	Select the TransferByteRate parameter of the second controller 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. Compare the values to evaluate the workload distribution.

GRAPH_TransferByteRate_Comparison

Transfer Byte Rate Graph

For example, if the TransferByteRate parameter on one controller shows values significantly higher than the values of the other controller, the first controller may constitute the performance bottleneck in the array.

Administrators should pay close attention to which volume is handled by which controller, depending on the activity of these volumes, so that neither controller is overloaded. It is recommended to start by identifying LUNs that are not owned by their normal (default) controller.