vSAN Host Fails Full Data Migration Pre-Check with RAID-6 and Six Hosts
Article ID: 415685
Updated On:
Products
Issue/Introduction
When attempting to place one of the six hosts into maintenance mode using the "Full data migration" option. The following error occurs. "The host cannot enter maintenance mode. Resource check failed - There are currently 5 usable fault domains. The operation requires 1 more usable fault domain. Sample failed object: ########-####-####-####-#############
Environment
vSAN 9.x
vSAN 8.x
vSAN 7.x
Cause
The "Full data migration" option requires the vSAN cluster to rebuild all data components across the remaining active hosts to maintain full compliance (FTT=2) during maintenance. Removing one host from the 6-host cluster leaves only five active hosts, which is insufficient to satisfy the RAID-6 FTT=2 minimum requirement. See Failure Handling in vSAN
Resolution
To successfully place a host into maintenance mode in a 6-host RAID-6 cluster, you must use a less restrictive data migration option:
- When prompted for the maintenance mode option, select "Ensure accessibility".
This option allows the host to enter maintenance mode without attempting to fully migrate the RAID-6 components across an insufficient number of remaining hosts, thereby avoiding the PRE-CHECK failure.
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