An administrator uses the df -h command and notices that an NFS datastore is reporting a capacity of 0 Bytes. What condition would cause this to occur?

When the NFS server is unreachable or down, ESXi loses the ability to query the server for filesystem statistics such as total capacity and free space. Without a valid response from the server, the datastore capacity is reported as 0 bytes because no data can be returned.

Mounting an NFS datastore as Read/Write is the standard configuration and has no impact on capacity reporting - ESXi can query filesystem size regardless of write permissions.

A Read-Only NFS mount restricts write access but does not prevent ESXi from querying the server for capacity statistics, so size would still be reported correctly.

NFS version 4.1 is a fully supported protocol in vSphere and does not inherently cause capacity to report as 0 - connectivity loss, not protocol version, is the cause of this symptom.