An administrator is troubleshooting a vSAN issue.

The symptoms described—reduced cluster capacity,degraded virtual machine components, andautomatic component rebuild operations—are classic indicators of avSAN disk failure or disk group degradation. vSAN continuously monitors the health of disks, disk groups, and network paths. When a physical disk or disk group becomes unavailable, vSAN will:

Mark affected components as degradedbecause the required number of replicas or witnesses cannot be maintained.

Trigger automatic repair/rebuild operations, provided there are enough healthy disks remaining in the cluster to satisfy the storage policy (e.g., FTT=1, RAID1/5/6).

Reduce available storage capacitybecause the failed device is removed from contributing to the vSAN datastore.

These behaviors align directly with documented vSAN failure-response logic, which states thatcomponent rebuilds begin automatically after a disk failure, assuming the cluster still has adequate resources.

The other options do not match the symptoms:

A. VM migration to another cluster→ does not reduce vSAN capacity nor trigger component rebuilds.

B. vSAN license capacity too small→ restricts features, not component state or capacity changes.

C. Too many VMs created→ may cause capacity pressure but doesnotmark components degraded or trigger automated rebuilds.

Onlyphysical disk failureaccurately explains all three observations simultaneously.