vSAN Data Migration pre-check shows XXX non-compliant objects
search cancel

vSAN Data Migration pre-check shows XXX non-compliant objects

book

Article ID: 405096

calendar_today

Updated On:

Products

VMware vSAN VMware vSAN 7.x VMware vSAN 8.x

Issue/Introduction

  • When performing the Data Migration Pre-check (vSAN Cluster -> Monitor Tab -> vSAN -> Data Migration Pre-check) with the Ensure accessibility option, you see a warning indicating "xxx non-compliant objects" similar to the following:

Environment

  • VMware vSAN 7.x
  • VMware vSAN 8.x

Cause

  • This is expected behavior, depending on the specific VM policies in use and the number of hosts in the cluster.
  • The Ensure accessibility mode only evacuates enough of the VM object components to ensure that the VM will remain accessible. It does not guarantee full policy compliance and/or redundancy.

  • Here are a couple of common example scenarios where this occurs:

1) When placing one host in a 4 host cluster into maintenance mode when the VM's are using using a RAID-5 policy.

      • In this case, only 3 components for each object would remain will be available, since there would only be 3 available hosts in the cluster, so all objects using that  RAID-5 policy, which requires 4 hosts for full redundancy, would become non-compliant.
  •  

2) When using a RAID-1 policy (such as the vSAN Default Policy) in a cluster regardless of how many hosts would remain available (including when there are enough remaining hosts to satisfy the policies in use).  

      • The object components can be placed on any host in the cluster. When a host is placed into maintenance mode, only the components that are on that host's disk groups -and- would not have enough remaining components on the other hosts for those VM's to remain accessible, would be rebuilt on the remaining hosts. 
      • You may still see this on some VM's even if there are enough remaining hosts to support the VM's policy requirements.
      • The Ensure accessibility mode does not cause vSAN to rebuild the components immediately, unless the specific objects would become inaccessible. In this case, they would only be rebuilt after the Object Repair Timer expires. 

 NOTE: These are only 2 examples. There are many other cases where this can occur, depending on the specific policies, the number of hosts in the cluster, and  minimum number of hosts required for those policies. 

 

Resolution

  • If full redundancy is required, then you should choose the Full Data Migration for the data evacuation mode when placing the host into maintenance mode (NOTE: this may significantly increase the time to enter maintenance mode). See TechDocs: Place a Member of vSAN Cluster in Maintenance Mode

Additional Information

Powered by Wolken Software