A vSphere administrator needs to add more space to an existing 3-node Virtual SAN cluster. The attempts to add the new host to the cluster as a contributing member have failed. However, it can be adde

When the host was used as a standalone server, its SSD was formatted with a VMFS datastore for local storage, which places a partition signature on the disk that vSAN cannot claim. Virtual SAN mandates at least one SSD per contributing host to serve as the read and write cache tier within a disk group, and if that SSD is already consumed by a VMFS volume, vSAN has no cache device available and the host falls back to non-contributing status. The administrator must delete the VMFS datastore and release the SSD so it can be claimed by the vSAN disk group.

NIC speed mismatches between cluster members affect network throughput and latency but do not disqualify a host from being added as a contributing member to a Virtual SAN cluster.

Virtual SAN manages its own caching entirely through the claimed SSD and does not impose a minimum hardware RAID controller cache size as a prerequisite for contributing membership.

The capacity of existing VMFS datastores on magnetic disks has no bearing on contributing membership eligibility - what vSAN evaluates is whether an SSD is available and unclaimed for the disk group cache tier.