Merge pull request #11731 from soapy1/nfs-troubleshooting-guide

Outline common troubleshooting steps for nfs

website/pages/docs/synced-folders/nfs.mdx

@@ -234,3 +234,42 @@ For more information about transport protocols and NFS version 4 see:
 
 - NFSv4.0 - [RFC7530](https://tools.ietf.org/html/rfc7530#section-3.1)
 - NFSv4.1 - [RFC5661](https://tools.ietf.org/html/rfc5661#section-2.9.1)
+
+## Troubleshooting NFS Issues
+
+NFS issues may arise for a variety of reasons. The  following list
+describes how to possibly identify the root of the issue.
+
+* Ensure nfs server is running on the host. Check if it is running using 
+  the command `ps aux | grep nfsd`. If the nfs service is not running, 
+  then it may require a manual restart.
+
+* If using Mac, ensure that `/sbin/nfsd` has been given Full Disk Access.
+
+* Ensure the synced folder is present in the hosts `/etc/exports` file.
+  If the target folder is not listed in  `/etc/exports`, then ensure that
+  the synced_folder option `nfs_export` is set to `true`, or manually add
+  the entry.
+
+* Ensure that the contents of `/etc/exports` is valid. For example, if running
+  nfsd, this can be done by running `nfsd checkexports`.
+
+* Ensure guest machine has a nfs client installed. The client may differ
+  depending on the OS. If no nfs client is installed on the guest, then it may
+  need to be installed.
+
+* Ensure the guest has access to the mounts. This can be done using something
+  like the `rpcinfo` or `showmount` commands. For example `rpcinfo -u <ip> nfs`
+  or `showmount -e <ip>`.
+
+* Ensure a firewall is not blocking NFS.
+
+* Try manually mounting the folder, enabling verbose output:
+    ```
+    $ vagrant ssh
+    $ mount -v -t nfs -o <mount options> <ip address>:<path to folder on host> <mountpoint>
+    ```
+
+* If using a UDP connection: ensure UDP is enabled by the nfs server. This setting
+  can likely be changed in config file `/etc/nfs.conf`. Or, in Vagrant, set the
+  `nfs_udp` option for the synced folder to `false`.