Tuning NFS Server exports file for performance

Tuning NFS Server exports file (/etc/exports) for performance. As far as I know, these 2 options are the most important

  1. async: The default export behavior for both NFS Version 2 and Version 3 protocols, used by exportfs is “asynchronous”. According to Optimizing NFS Performance. This default permits the server to reply to client requests as soon as it has processed the request and handed it off to the local file system, without waiting for the data to be written to stable storage. This is indicated by the async option denoted in the server’s export list. It yields better performance at the cost of possible data corruption if the server reboots while still holding unwritten data and/or metadata in its caches. This possible data corruption is not detectable at the time of occurrence, since the async option instructs the server to lie to the client, telling the client that all data has indeed been written to the stable storage, regardless of the protocol used.
  2. no_subtree_check: For NFS version 1.0.x and above, To speed up transfer, disable subtree check especially if you are exporting large directory.
/tmp *(rw,async,no_subtree_check)

For other good materials on the /etc/exports, do check out
http://linux.die.net/man/5/exports