Foglight for Storage Management Shared 4.4.5

Perform Pool Change Analysis. The Pool Change analyzer identifies the LUNs primarily responsible for increased I/O. It compares LUN activity in the problem time range with LUN activity during the same time range in the past. Changes are reported in terms of average operations rate and change amount.

•

Perform Pool Load Analysis. The Pool Load analyzer identifies the busiest LUNs and ranks them based on their activity during the same time range over the last 30 days (not the current time frame). Activity is measured in operations per second.

To analyze the pool:

From the Server-Side Analysis window or the Pool Explorer window, click Perform Pool Change Analysis.

The analyzer compares activity for all the LUNs in the pool during the problem time range with their activity a week ago. In this example, the table and pie chart confirm that the LUN with the highest average operations rate and change amount is the LUN that includes the disk extent used by the poor performing virtual machine.


	TIP: You can change the comparison time range by clicking Change and selecting a new date and time range.

Close the window.

Click Perform Pool Load Analysis.

The chart and table show the top ten busiest LUNs. The analysis is based on the last 30 days of activity during this time range. In this example, the table confirms that the top two busiest LUNs are connected to the poor performing virtual machine.

Close the window.

The investigation is complete.

Changing Latency Thresholds

One way Foglight for Storage Management determines if the performance problem is occurring in the SAN storage environment is to evaluate latency against the thresholds defined for latency in registry variables. The latency thresholds used for analysis are, by default, the same thresholds as are used for generating latency alarms. If you think it would be helpful to adjust the threshold values for your analysis, you can change the threshold values using the Storage Troubleshooting dashboard. The original registry variables are not updated.


	TIP: If you change thresholds, you can restore the default values later using the Reset button.

To change the latency thresholds:

In the Storage Troubleshooting dashboard, click Edit Thresholds.

Specify the new thresholds in milliseconds for one or both of Warning and Critical.

Click Apply.

Understanding the Troubleshooting Algorithm

To determine if the problem is likely to be a storage performance problem, Foglight for Storage Management evaluates latency metrics against thresholds and typical performance, and disk extent metrics against the I/O being performed to the extent by the virtual machine. If the likely cause of the problem is slow performance in the SAN Storage environment, Foglight for Storage Management examines the LUN or NASVolume. If no circumstances, such as a rebuild, are identified as a cause of high latency, the pool is examined.

Managing Data Collection, Rules, and Alarms


	NOTE: This section is intended for users with the role Storage Administrator. Some tasks also require the Foglight for Storage Management role of Administrator (as noted) to manage agents and rules.

You can collect additional types of relationship data, change collection schedules, manage rules, and manage alarms.

•

Collecting Virtual Storage-to-SAN Relationships

•

Inferring Physical-Host-to-Storage Relationships

•

Modifying Data Collection Schedules (Administrator role required)

•

Managing Foglight for Storage Management Rules (Administrator role required)

•

Managing Alarm Settings

•