Below are list of options used in /etc/exports file :

1. ro: The directory is shared read only; the client machine will not be able to write to it. This is the default.
2. rw: The client machine will have read and write access to the directory.
3. root_squash: By default, any file request made by user root on the client machine is treated as if it is made by user nobody on the server. (Exactly which UID the request is mapped to depends on the UID of user “nobody” on the server, not the client.)
4. no_root_squash : if this option is used , then root on the client machine will have the same level of access to the files on the system as root on the server. This can have serious security implications, although it may be necessary if you want to perform any administrative work on the client machine that involves the exported directories. You should not specify this option without a good reason.
5. no_subtree_check : If only part of a volume is exported, a routine called subtree checking verifies that a file that is requested from the client is in the appropriate part of the volume. If the entire volume is exported, disabling this check will speed up transfers.
6. SYNC : REPLIES to the NFS request only after all data has been written to disk. This is much safer than async, and is the default in all nfsutils versions after 1.0.0.
7. async : Replies to requests before the data is written to disk. This improves performance, but results in lost data if the server goes down.
8. no_wdelay : NFS has an optimization algorithm that delays disk writes if NFS deduces a likelihood of a related write request soon arriving. This SAVES disk writes and can speed performance
9. wdelay : Negation of no_wdelay , this is default
10. nohide : Normally, if a server exports TWO filesystems one of which is mounted on the other, then the client will have to mount both filesystems explicitly to get access to them. If it just mounts the parent, it will see an empty directory at the place where the other FILESYSTEM is mounted. That filesystem is “hidden”. Setting the nohide option on a filesystem causes it not to be hidden, and an appropriately authorised client will be able to move from the parent to that filesystem without noticing the change.
11. hide : Negation of nohide This is the default

Below are list of options used in /etc/exports file :