When doing a tar -xzf ... of a big source tar on an NFSv4 file system the time taken is huge. I am seeing an overall data rate of about 1 MByte per second across the network interface. If I copy a single large file I see a network data rate of about 110 MBytes/sec which is about the limit of the Gigabit Ethernet interface I am using.
Now, in the past I have used the NFS "async" mount option to help with write speed (lots of small files in the case of an untar of a set of source files).
However, this does not seem to speed this up in Fedora27 and also I don't see the "async" option listed when I run the "mount" command. When I use the "sync" option it does show up in the "mount" list.
The question is, is the "async" option actually working with NFS v4 in Fedora27 ?