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Virtual SAN Observer – Offline Monitoring Bundle Issue

Virtual SAN ObserverI recently published an article describing the procedure to configure and enable the VMware Virtual SAN Observer tool to work without the requirement of Internet access. This operating mode is known as the offline-mode.

VMware Virtual SAN Observer Offline Mode article

The Virtual SAN Observer tool provides three different options for monitoring statistics. The offline monitoring option is probably the most utilized option out of the three as it presents the most flexibility for archiving and data transportability. A brief description of the Virtual SAN Observer monitoring modes is listed below.

Virtual SAN Observer Monitoring Modes

  • Live Monitoring – This mode displays the performance statistics in real time as they are being generated by the system.
  • Offline Monitoring – This mode provides the ability to create a tar.gz package with html bundle which can be utilized for archiving purposes or future inspection.
  • Full raw status bundle – This mode provides the ability to collect all the stats into a large JSON file for deeper analysis.

I have identified a bug which breaks the use of the Offline Monitoring mode after setting up the Virtual SAN Observer to work in the offline. The bug prevents the creation of the html files that are required for the successful creation of the tar.gz offline bundle. Knowing that the Virtual SAN Observer offline monitoring mode is one of the most utilized out of the three methods, I felt obliged to provide a quick fix for the issue immediately and not wait until the bug is patched.

I would like to reiterate that much like the requirements defined in my previous post with regards to the VMware Virtual SAN Observer Offline Mode article, this fix is only applicable to vCenter Server U2.


After the Virtual SAN Observer is configured to work in the offline mode, the necessary html files for the tar.gz package fail to generate when the statistics collection process is completed. The RVC console produces an error similar to the one displayed below:



A syntax bug causes the issue only after the Virtual SAN Observer is configured to work in the offline mode. In order to correct the problem, exit out of the RVC utility and back onto the shell of the vCenter Server Appliance. Use the following command to make the necessary changes to correct the syntax problem:

sed -i ‘s:File.basename):File.basename(f)):’ /opt/vmware/rvc/lib/rvc/modules/vsan.rb


After the change is made, all of the required html files will be successfully created and stored in the tar.gz offline bundle.  A fix for this issue will be included in a future patch release.

–       Enjoy

For future updates on Virtual SAN (VSAN), Virtual Volumes (VVols), and other Software-defined Storage technologies as well as vSphere + OpenStack be sure to follow me on Twitter: @PunchingClouds

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