VM backup fails while one node in the vSAN cluster is in maintenance mode
Article ID: 428941
Updated On:
Products
Issue/Introduction
- A vSAN cluster is configured with six nodes (ESXi hosts) and utilizes RAID-6 as the FTT.
- One node is placed into maintenance mode using the "Ensure Accessibility" option.
- Virtual machine backups fail during the snapshot creation phase.
Environment
VMware vSAN
Cause
Minimum nodes requirements for each "Failures tolerate" (FTT) setting in the VM storage policy are listed below:
| Failures to tolerate | Minimum nodes required |
| 1 failure - RAID-1 (Mirroring) | 3 |
| 1 failure - RAID-5 (Erasure Coding) | 4 |
| 2 failure - RAID-1 (Mirroring) | 5 |
| 2 failure - RAID-6 (Erasure Coding) | 6 |
| 3 failure - RAID-1 (Mirroring) | 7 |
In a vSAN cluster configured with the minimum number of nodes required for a specific policy (such as RAID-6 requiring 6 nodes), if one node is in maintenance mode and unavailable to vSAN, the cluster cannot satisfy the VM storage policy requirements. Consequently, the creation of new objects, including snapshots, is prevented.
Resolution
As a temporary workaround during maintenance, edit the VM storage policy being used and enable "Force Provisioning."
This allows snapshots and other new objects to be created even if they do not currently comply with the redundancy requirements of the policy.
Edit or Clone a VM Storage Policy
Once the node maintenance is complete and the host is back online, disable "Force Provisioning" to return to the standard compliant state.
Note: It is NOT recommended to continue normal operations with "Force Provisioning" enabled, as it bypasses the intended data protection levels.
Additional Information
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