RHEL8: Does NFS I/O count as part of "%iowait" calculations?
Solution 1:
Yes, on Linux, NFS is included in iowait time, and contributes to the load average.
Red Hat KB Does NFS cient I/O count iowait% on linux? shows packet loss to an NFS server increasing iowait. Eventually your NFS server may go away unexpectedly, try looking at iostat in that bad state.
Tasks that sleep on I/O contribute to these iowait metrics in process accounting. NFS does this, it calls io_schedule().
"Disk" is a shorthand for processes waiting on I/O, which typically but not always are block devices.