[Question] Sangfor Witness Node with 2Node + witness(VM) - Virtual Datastore

Newbie481305 Lv1Posted Aug-26-2025 09:26

I am currently attempting to configure a Virtual Datastore using a 2-node Sangfor HCI cluster with an additional Witness Node.

All the basic configurations on the 2 physical nodes have been completed. I have created a VM on the ESXi host to serve as the Witness Node, using the provided OVF image. My intention is to create a Virtual Datastore using these 2 physical Sangfor nodes along with the VM Witness Node.

Since it is a 2-node setup, I selected the Ordinary Mode. However, upon finalizing the configuration, the following error occurred:


"The witness node for a stretched datastore cannot be selected to create a datastore using two nodes."

According to the manuals and previous explanations, it is my understanding that a 2-node configuration with a Witness Node should be possible. Could you please clarify why this error is occurring and advise on how to proceed?

Thank you very much for your assistance.

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In Sangfor HCI, the witness node is only used in specific scenarios:
- 2-Node Clusters > witness is required for quorum.
- Stretched Clusters > witness node monitors availability between sites.

However, the witness node itself is not a data-bearing node. It does not participate in datastore creation. Its role is limited to arbitration (tie-breaker if one node goes down).

The error message:
“The witness node for a stretched datastore cannot be selected to create a datastore using two nodes.”
means you mistakenly tried to include the witness node in the Virtual Datastore creation, but only the two physical nodes should be used when creating a datastore.

Try this:

1. Deploy Witness Node
- Deploy the provided OVF/OVA as a VM (as you did).
- Register it in the Sangfor HCI cluster as a Witness (not as a storage node).

2. Cluster Configuration
- In Cluster Settings, bind the witness node to the 2-Node cluster.
- Confirm it shows as a Witness Node in cluster status.

3. Create Virtual Datastore
- When creating the datastore, select only the two physical HCI nodes as members.
- Do not include the witness node, it won’t store or replicate data.

4. Verification
- After datastore creation, the witness node will appear under Quorum Management.
- The datastore redundancy will show as “2 replicas + witness arbitration.”

The witness node never stores data. It only provides quorum/heartbeat so the 2-Node datastore can survive a single node failure without split-brain. That’s why the system rejected your attempt, you must exclude the witness from datastore creation.

Feel free to correct me here, thanks.
Is this answer helpful?
Newbie337989 Lv2Posted Aug-26-2025 10:39
  
In Sangfor HCI, the witness node is only used in specific scenarios:
- 2-Node Clusters > witness is required for quorum.
- Stretched Clusters > witness node monitors availability between sites.

However, the witness node itself is not a data-bearing node. It does not participate in datastore creation. Its role is limited to arbitration (tie-breaker if one node goes down).

The error message:
“The witness node for a stretched datastore cannot be selected to create a datastore using two nodes.”
means you mistakenly tried to include the witness node in the Virtual Datastore creation, but only the two physical nodes should be used when creating a datastore.

Try this:

1. Deploy Witness Node
- Deploy the provided OVF/OVA as a VM (as you did).
- Register it in the Sangfor HCI cluster as a Witness (not as a storage node).

2. Cluster Configuration
- In Cluster Settings, bind the witness node to the 2-Node cluster.
- Confirm it shows as a Witness Node in cluster status.

3. Create Virtual Datastore
- When creating the datastore, select only the two physical HCI nodes as members.
- Do not include the witness node, it won’t store or replicate data.

4. Verification
- After datastore creation, the witness node will appear under Quorum Management.
- The datastore redundancy will show as “2 replicas + witness arbitration.”

The witness node never stores data. It only provides quorum/heartbeat so the 2-Node datastore can survive a single node failure without split-brain. That’s why the system rejected your attempt, you must exclude the witness from datastore creation.

Feel free to correct me here, thanks.

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