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 amount of data being read/written on a physical disk is well-balanced over time across all physical disks, you need to compare the throughput of read/write data for each physical disk in your EMC storage systems.

To compare the I/Os of physical disks, you will need to create a simple one-row dashboard. Dashboards allow you to gather specific types of data and display them in a consolidated graphical format. For detailed information about dashboards options and features, refer to the BMC documentation.

To Diagnose a Bad Disk Layout

1.	Login to your BMC TrueSight Operations Management console.

2.	Select Dashboards from the navigation pane.

3.	In the Dashboards page, click Add Dashboard or select Add Dashboard from the dashboard action menu .

Dashboard_Add

4.	Enter a Title for your dashboard and configure a Global Filter, if needed.

5.	Click Add Dashlet to open the dashlet library for the first column of the row.

6.	From the dashlet library, select the Device Performance template, and then click Close.

Dashlet_Add_EMC Disk_Layout

7.	Select Configure Dashlet by clicking the button.

8.	In the panel of input fields and options that opens below the dashboard, enter a Title for the dashlet and specify a Refresh Rate (default is 5 minutes).

9.	Select the EMC storage device for which you to compare physical disks I/Os.

10.	Select the Read Byte Rate and Write Byte Rate parameters for the first physical disk, and click Apply.

Dashlet_Configure EMC Disk_Layout

Tip

To quickly retrieve a component or a parameter, enter its name in the Search Parameters field and click Search.

11.	Repeat this operation in the next column(s) of the dashboard with other physical disks and click Save.

12.	The dashboard is completed and shows the Read Byte Rate and Write Byte Rate for the selected physical disks.

Dashboard_EMC Disk_Layout

Verify that the I/Os are well-balanced across all physical disks. Make sure that the Read Byte Rate and Write Byte Rate of all the physical disks have similar average values.