HP CIFS Opportunistic Locking Usage Guidelines

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Chapter 5 Summary
Windows Opportunistic Locking is a lightweight performance-enhancing feature. It is not a
robust and reliable protocol. Every implementation of Opportunistic Locking should be
evaluated as a tradeoff between perceived performance and reliability. Reliability decreases
as each successive rule above is not enforced. Consider a share with oplocks enabled, over a
wide area network, to a client on a South Pacific atoll, on a high-availability server, serving a
mission -critical multi-user corporate database, during a tropical storm. This configuration
will likely encounter problems with oplocks.
Oplocks can be beneficial to perceived client performance when treated as a configuration
toggle for client-side data caching. If the data caching is likely to be interrupted, then oplock
usage should be reviewed. CIFS/9000 Server and Samba enable opportunistic locking by
default on all shares. Careful attention should be given to the client usage of shared data on
the server, the server network reliability, and the opportunistic locking configuration of each
share.