Use statistics to monitor automatic node referral activity

Contributors

To determine how many SMB connections are referred, you can monitor automatic node referral activity by using the statistics command. By monitoring referrals you can determine the extent to which automatic referrals are locating connections on nodes that host the shares and whether you should redistribute your data LIFs to provide better local access to shares on the CIFS server.

About this task

The cifs object provides several counters at the advanced privilege level that are helpful when monitoring SMB automatic node referrals:

  • node_referral_issued

    Number of clients that have been issued a referral to the share root’s node after the client connected using a LIF hosted by a node different from the share root’s node.

  • node_referral_local

    Number of clients that connected using a LIF hosted by the same node that hosts the share root. Local access generally provides optimal performance.

  • node_referral_not_possible

    Number of clients that have not been issued a referral to the node hosting the share root after connecting using a LIF hosted by a node different from the share root’s node. This is because an active data LIF for the share root’s node was not found.

  • node_referral_remote

    Number of clients that connected using a LIF hosted by a node different from the node that hosts the share root. Remote access might result in degraded performance.

You can monitor automatic node referral statistics on your storage virtual machine (SVM) by collecting and viewing data for a specific time period (a sample). You can view data from the sample if you do not stop data collection. Stopping data collection gives you a fixed sample. Not stopping data collection gives you the ability to get updated data that you can use to compare against previous queries. The comparison can help you identify performance trends.

Note

To evaluate and use the information you gather from the statistics command, you should understand the distribution of clients in your environments.

Steps
  1. Set the privilege level to advanced: set -privilege advanced

  2. View automatic node referral statistics by using the statistics command.

    This example views automatic node referral statistics by collecting and viewing data for a sampled time period:

    1. Start the collection: statistics start -object cifs -instance vs1 -sample-id sample1

      Statistics collection is being started for Sample-id: sample1
    2. Wait for the desired collection time to elapse.

    3. Stop the collection: statistics stop -sample-id sample1

      Statistics collection is being stopped for Sample-id: sample1
    4. View the automatic node referral statistics: statistics show -sample-id sample1 -counter node

      Object: cifs
      Instance: vs1
      Start-time: 2/4/2013 19:27:02
      End-time: 2/4/2013 19:30:11
      Cluster: cluster1
      
          Counter                                             Value
          ----------------------------- ---------------------------
          node_name                                          node1
          node_referral_issued                                    0
          node_referral_local                                     1
          node_referral_not_possible                              2
          node_referral_remote                                    2
          ...
      
          node_name                                          node2
          node_referral_issued                                    2
          node_referral_local                                     1
          node_referral_not_possible                              0
          node_referral_remote                                    2
          ...

      Output displays counters for all nodes participating in SVM vs1. For clarity, only output fields related to automatic node referral statistics are provided in the example.

  3. Return to the admin privilege level: set -privilege admin

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