An all-flash vSAN cluster contains a sufficient number of capacity devices and cache devices to support different RAID levels.

FTT=3(RAID-1 Mirroring) - This policy requires at least 4 capacity devices, where each object is mirrored across three copies of the object. This can be satisfied by the 4 nodes all-flash vSAN cluster.

FTT=1 (RAID-1 Mirroring) - This policy requires at least 2 capacity devices, where each object is mirrored across one copy of the object. This can be satisfied by the 4 nodes all-flash vSAN cluster.

FTT=2 (RAID-6 Erasure Coding) - This policy requires at least 6 capacity devices, where each object is striped across two sets of parity and data. This cannot be satisfied by the 4 nodes all-flash vSAN cluster.

FTT=1 (RAID-5 Erasure Coding) - vSAN does not support RAID-5 Erasure coding.

To verify object resynchronization progress and impact after a global policy change, you can use vRealize Log Insight (C). According to the VMware Official Guide, “The vRealize Log Insight dashboard can be used to verify object resynchronization progress and impact after a global policy change.”