Monitoring Performance

Related Topics

Important:

How to Start Performance Monitoring

1

From the Subsystem Management Window, do one of the following:

  • Select the Performance Monitor toolbar button .
  • Select the Storage Subsystem >> Monitor Performance pull-down menu option.
  • Select the storage subsystem node in the Logical View, then Monitor Performance from the right-mouse pop-up menu.

    Result: The Performance Monitor dialog is displayed.

2

Select Settings to specify the logical drives and/or controllers to monitor and to specify the polling interval.

Tip: Logical Drives are sorted alphabetically, based on controller ownership, making it easier to locate a specific logical drive in the Select items to monitor area.

To change the polling interval, choose a number of seconds in the spin box. Each time the polling interval elapses, the Performance Monitor re-queries the storage subsystem and updates the statistics in the table.

3

Select Start.

Result:

  • The Start: field at the bottom of the dialog records the current date and time. This information is displayed on the screen until you select Stop. (When you select Stop, the Stop: field at the bottom of the dialog records the stop date and time).
  • The Time Monitored: field displays the elapsed time between the present time and the time Start was selected.
  • Important: For an accurate elapsed time, do not use the Set Controller Clocks option while using the Performance Monitor.
  • Values are displayed for the selected devices in the Performance Monitor data table. It is updated at the interval specified in the Polling Interval setting. Select Update to force an immediate poll of the storage subsystem.

4

Select Stop to stop monitoring the storage subsystem.

How to Save Performance Data to a File

1

Select Save As on the Performance Monitor main screen to save the currently displayed performance statistics.

Result: The Save Performance Statistics dialog is displayed.

2

Save the selected events by choosing an appropriate directory.

The Save dialog can filter on files with a .perf extension. Therefore, you may want to save the file with a .perf extension using the filename conventions you used for any previous performance monitor statistics files. The .perf extension is the default.

3

Type the file name of your choice in the File name text box.

Example: Name the file feb14A.perf.

4

Select the file type of your choice in the Files of type text box.

File Type

Select this type when...

Report Format (ASCII text)

You want to save the data in a report form for viewing or printing.

Comma Delimited Format

You want to save the data in a form that can be imported into a commercial spreadsheet application for further analysis (most leading commercial spreadsheet applications recognize a comma delimiter and use the delimiter to import the data into spreadsheet cells appropriately).

5

Select Save.

Result: A file containing the performance statistics, with a .perf extension or another extension you have specified, is saved to the directory.

About Storage Subsystem Performance Data

The Performance Monitor data provides information about how your storage subsystem is performing. The data is presented in eight columns, described in the table below. Use this data to make performance tuning decisions for your storage subsystem.

Column

Description

Devices

The Device column can display the following values:

  • Controller, shown as Controller in Slot A or B - Represents the totals for all logical drives owned by the controller, not just the logical drives presently selected for monitoring.
  • Logical Drive, shown as Logical Drive name, where Logical Drive name is the name assigned to the logical drive.
  • Storage Subsystem Totals - represents the totals for both controllers in an active-active controller pair, regardless if one, both, or neither are selected for monitoring.

Total I/Os

The number of total I/Os performed by this device since Start was selected. When this number exceeds 99,999, it is displayed in thousands (K), beginning with 100K until the number reaches 9999K, at which time it is displayed in millions (M). For amounts greater than 9999K but less than 100M, the value is displayed in tenths (for example, 12.3M).

Read Percentage

The percentage of total I/Os (previous column) that are read operations for this device. Write percentage can be calculated as 100 minus this value.

Cache Hit Percentage

The percentage of reads that are fulfilled by data from the cache rather than requiring an actual read from disk.

Current KB/second

The current KB per second, or transfer rate. Current means the number of KB per second since the last time the polling interval elapsed, causing an update to occur, or since Update was selected.

Maximum KB/second

The highest value achieved by the current KB per second column for this polling session (since Start was selected).

Current IO/second

The current I/Os per second. Current means the number of I/Os per second since the last time the polling interval elapsed, causing an update to occur, or since Update was selected.

Maximum IO/second

The highest value achieved by the current I/Os per second column for this polling session (since Start was selected).

Related Topics

Learn About Specifying Performance Monitor Settings

Setting Storage Subsystem Controller Clocks

Learn About Tuning Storage Subsystem Performance

Learn About Segment Size and Performance