VNX – Enabling & Collecting Performance Data (NAR Data)

In this segment I will walk you through how to enable and collect performance data on an EMC VNX series storage array. The EMC VNX storage array has the ability to collect and archive performance statistics in to what are known as “NAR” files. These performance archive files have been used by EMC’s mid-tier line of storage products (VNX / Clariion) for some time.

Below, I will walk you through step-by-step how to enable performance logging, set the collection interval and export a NAR file via Unisphere (EMC’s graphic user interface for VNX) from the storage array to your own computer.

*The steps and screenshots outlined below are based on a VNX system running version 31 of the block operating code (sometimes referred to as FLARE 31 or BLOCK OE 31). Past and future version of Unisphere (on both VNX and Clariion) allow for similar steps but may not be exactly what is outlined below.

(Click the images below to see a more detailed view)

Step 1) Login to Unisphere and select the array from the drop down at the top of the interface:



Step 2) Click the “System” button at the top of the interface.


Step 3) Click “System Properties” on the right side of the interface.


Step 4) Ensure “Statistics Logging” is enabled under the general tab of the system properties dialog box.


Step 5) Hover (mouse over) the “System” button at the top of the interface. Then click “Monitoring & Reporting”.


Step 6) Click “Statistics for Block”.


Step 7) Under the “Settings” panel click “Performance Data Logging”.


Step 8) Ensure Data Logging is running with the correct settings.

  • Set the intervals to desired values. Typically “60” seconds for “Real Time” and “300” seconds for “Archive” is sufficient.   Make sure you click “Apply” or “OK” if you change these values.
  • Enable “Periodic Archiving”. This allows the array to periodically write a NAR data to the service processor rather than wait until you request one.   Make sure “Status” at the bottom of the dialog box is “Running”. If it isn’t click the “Start” button.
  • When finished, click “OK” to close the dialog box.


Additional Information :

The interval determines how often stats are capture from the array. The “Real Time” value is used for SPA and the “Archive” value is used for NAR Data.

A smaller interval will give us more accurate information but also increases the effort to collect the data and increases how large the collection of data ends up being.




Step 9) Click “Retrieve Archive” from the “Statistics for Block” menu (you should already be here based on previous steps).

 Additional Information:

If you just enabled data collection, at least (10) increments of the “Archive Interval” must have passed before you can create a NAR file on the controller. Meaning, if your “Archive Interval” was “300” seconds then 3000 seconds (about an hour) would have needed to pass before the system will allow you to “Create a New” NAR file.

Typically, you want to let data collection run at least 1 full day with  7 days being ideal to get a full picture of your storage environment.



Step 10) Create and collect the NAR files from the storage controller.

  • After (Step 9) the “Retrieve Archive” dialog box (below) should pop up.
  • If there are existing NAR files you can choose one or many (using shift / ctrl) from the file details box, selecting a destination folder in the “Save File(s) As:” section and then clicking the “Retrieve” button.

Additional Information:

If no files NAR files exist you can force the create of a NAR file by clicking the “Create New” button. The minimum interval period mentioned above would have needed to pass otherwise the file will not be created.

SP A and SP B should collect the same performance information. It is best practice to collect data from both controllers (to allow you to validate accuracy), but in practice only data from one controller is actually needed.

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4 comments on “VNX – Enabling & Collecting Performance Data (NAR Data)
  1. Vivek says:

    Thanks for Steps..IT helped me .

  2. Laurent says:

    You rocks !!! thanks dude 🙂

  3. Aman says:

    Very Nice Write Up!!

  4. Sid says:

    U r a Champ Brother. Thanks for the efforts to help others.

    Cheers 🙂 Thumbs Up. Keep it coming

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