A vSAN Administrator has a cluster of six vSAN nodes. The vSAN datastore was 55% utilized, and due to a power outage, one node was lost. The vSAN administrator needs to resolve the storage policy compliance for the virtual machines on RAID-5.
Which action, if any, needs to be taken to meet this goal?
A. No action is needed since vSAN automatically rebuilds the objects.
B. The one failed node must be restored.
C. Trigger vSAN object repair from ESXCL
D. Change the RAID-5 FTT from 2 to 1.
Explanation:
When a node is lost in a vSAN cluster, the vSAN will automatically begin to rebuild objects in order to meet the storage policy compliance. However, if the storage policy includes RAID-5 with a "Failures to Tolerate" (FTT) value of 2, it won't be possible to rebuild the objects and meet the storage policy compliance with only 5 nodes. In this case, the vSAN administrator needs to change the RAID-5 FTT from 2 to 1, this will allow the vSAN to rebuild the objects and meet the storage policy compliance with only 5 nodes. With RAID-5, the FTT value of 1 is the minimum value supported by vSAN.
This is explained in VMware vSAN documentation in the section "RAID-5 and RAID-6 Erasure Coding"
Reference: https://docs.vmware.com/en/VMware-vSphere/7.0/vsphere-vsan-70-config-guide/GUID-1A5F48D5-F8C9-4C7E-9D9B-F9D4B4E4A4F4.html Changing the RAID-5 FTT from 2 to 1 will ensure that the virtual machines on the vSAN datastore are in compliance with the storage policy. This is because, with a RAID-5 FTT of 2, the cluster needs at least 6 nodes to meet the redundancy requirements. With a single node lost, the cluster cannot meet this requirement and so the virtual machines on the datastore will be out of compliance. By changing the FTT from 2 to 1, the cluster will be able to meet the redundancy requirements with only the remaining 5 nodes, ensuring compliance with the storage policy.
Reference: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.troubleshooting.doc/GUID-F7A0FECC-E95E-4A89-B3B3-9699D9F7D87D.html