vSAN -- Convert 2-Node Stretched Cluster to a Standard Cluster
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vSAN -- Convert 2-Node Stretched Cluster to a Standard Cluster

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Article ID: 384761

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Updated On:

Products

VMware vSAN

Issue/Introduction

Convert a 2-Node Stretched Cluster to a Standard vSAN Cluster by adding additional Host(s)

 
Optional:
Remove vSAN Hosts while converting to a Standard vSAN Cluster.
Please note that the final Standard vSAN Cluster needs to consist of a minimum of 3 vSAN Hosts (= no Witness) contributing Storage to vSAN to be fully operational ( Reference ).

Environment

vSAN 7.0
vSAN 8.0

Resolution

A.) Complete the following tasks in preparation for converting to a Standard vSAN Cluster  (= 3 Hosts or more / No Witness) 
 
1.) Ensure that proper Licensing is available since ROBO Cluster License will not work
See for more information the vSAN License Requirements
If in doubt, open non-Technical Ticket with VMware by Broadcom Licensing Team

2.) Ensure that new vSAN Host(s) are meeting the requirements in regards to Hardware, Cluster, Software and Network
3.) Ensure that the new vSAN Host(s) are on the same Build as the existing vSAN Hosts
4.) If the final converted Standard vSAN Cluster will exist of a total of 3 Hosts, please review Limitations of a Two-Host or Three-Host Cluster Configuration

5.) Review the current vSAN Skyline Health for any issues which need to be resolved prior to starting the conversion
If needed make some note of the existing Warnings/Alerts for later review (= Step 7 below)
 
 

B.) Proceed with the Conversion of the 2-Node Cluster (ROBO) to a Standard vSAN Cluster by following:
 
1.) Convert the 2-Node Stretch Cluster to a Standard vSAN Cluster
Please note that after the steps have been completed:
- The VMs residing on this Cluster should be functional
- The Cluster is not in a fully functional state because it is not meeting the minimum requirement for Operation of a regular Cluster which is: 3 vSAN Hosts (= no Witness).
Therefore Step 7.0 "Repair the objects in the cluster" mentioned in the link above will not work.
We first need to follow the next steps to add Host(s) to the Cluster. 
 
2.) Verify that the correct License shown under the License settings in vSAN
 
3.) Add at least one new Host to existing vSAN 2-Node Stretch Cluster
Please note:
The "Verify that the vSAN Disk Balance health check is green" mentioned in the link above, might not be green at first. This is not an concerning issue.
Re-evaluate after completion of Step 8.) or Step 10.) outlined below.
 
4.) Configure Disk Groups (OSA Model) or Storage Pool (ESA Model) on new Host(s)
 
5.) Verify that all new Disk Groups or Storage Pool have been created and looking healthy (= green) in the Disk Management
6.) If the new Host(s) are in Maintenance Mode, take them out of Maintenance Mode. At this point you should not have any vSAN Host(s) in Maintenance Mode.
 
7.) Verify that the vSAN Skyline Health is not showing any new concerning alerts compared to how it looked prior to converting the vSAN Cluster (= above: Step 5 under Section A.) )
 
8.) Wait with any further Maintenance tasks until any running Resync has been completed
Review Resynchronization

 
 
Optional: Follow the next steps if you plan to remove any vSAN Host(s) 
 
9.) After any Resync has been completed, proceed with removing the desired vSAN Host(s)
Permanently Decommissioning a Host
Please note that you final Regular vSAN Cluster needs to consist of a minimum of 3 vSAN Hosts (= no Witness)
contributing Storage to vSAN to be fully operational ( Reference ).
 
10.) Wait with any further Maintenance tasks until any running Resync has been completed
Review Resynchronization
 
 
 
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