The configuration maximum for vSAN 6.x is 64 nodes per cluster, by default you can only have 32 nodes in the cluster.
To enable support for more than 32 nodes per cluster, you need to follow the steps outlined in KB 2110081
I am going to walk you through what happens if you go over the 32-node default maximum and how to verify the settings once you made the changes outlined in KB 2110081
When you add the 33rdnode to default vSAN cluster that cluster will show up second VSAN partition. The 34thnode will show up as the third partition, the partition number will continue to increase with each host you add after 32.
You can verify the host is not in the cluster with command ” esxcli vsan cluster ” the epected resault for the patition host will look like this:
Cluster InformationEnabled: true
Enabled: trueCurrent Local Time: 2018-07-17T5:23:35
Current Local Time: 2018-07-17T5:23:35 Local Node UUID: 57e1234c-83a9-add9-ec1f-0cc47ab35674
Local Node UUID: 57e1234c-83a9-add9-ec1f-0cc47ab35674
Local Node Type: NORMAL
Local Node State: MASTER
Local Node Health State: HEALTHY
Sub-Cluster Master UUID: 57e1234c-83a9-add9-ec1f-0cc47ab35674
Sub-Cluster Backup UUID:
Sub-Cluster UUID: 57e1234c-83a9-add9-ec1f-0cc47ab35674
Sub-Cluster Membership Entry Revision: 0
Sub-Cluster Member Count: 1
Sub-Cluster Member UUIDs: 57e1234c-83a9-add9-ec1f-0cc47ab35674
Sub-Cluster Membership UUID: 57e1234c-83a9-add9-ec1f-0cc47ab35674
You can also check to see if the host is listed uncast list with command “esxcli vsan cluster unicastagent” list to see if the host is present on the list.
Ok, we have verified that host is communicating and is in a cluster by itself time to make changes in noted in KB 2110081. Please note that vSAN 6.61 was used in the environment so we could skip step 4 of the KB.
After the host is rebooted, let’s verify that commands made the changes requested
Esxcli system settings advanced list –o /VSAN/goto11
Esxcli system settings advanced list –o /Net/TcpopHeapMax
At this point you will get Advanced vSAN configuration in sync warring this is expected until you made the change on every host.
Once you complete these steps on every host, the Advanced vSAN configuration sync will go away, and you will be able to add more than 32 hosts to your vSAN cluster.