Networking Guide
Chapter 12, Configuring the Network File System (NFS)

Setting block timeout

Setting block timeout

If a user requests a lock that already exists, the request is blocked (refused). Most locks exist only briefly. block_timeout is the interval that lockd will wait before retransmitting a blocked request to the server lockd. By default, lockd will wait 5 seconds before retransmitting the lock request. You can alter this by setting the -b flag when you invoke lockd on the client:

/etc/lockd -b 30

This will cause the local lockd to wait 30 seconds before retransmitting a blocked lock request to the server. It is generally desirable to change the block_timeout when you wish to minimize network traffic or if you are transmitting to a slow server.