What does an error message like this mean?: "afs: byte-range lock/unlock ignored; make sure no one else is running this program"

Answer

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This message indicates that some program running on this machine tried to lock or unlock a byte range of a file in AFS space. AFS only supports whole file locking.

Most file access is the same in AFS as with local files, which means that many applications run fine. AFS does not provide exact UNIX file semantics, however, which can cause problems in certain areas:

- locking: AFS does not support byte-range locking, which some applications use. In such cases, the AFS client code will generate a message on the console and/or on the terminal running the application indicating that byte-range locking is being ignored. The application will run, but problems may be encountered if multiple people are using the same application simultaneously. The current solution is to rewrite the application to not depend on byte-range locking, which is not always feasible with third-party software products.

Helpful hints -
o Lock whole files, not specific byte ranges.
o Use blocking locks, not non-blocking locks. Attempts to do non-blocking locks do not work properly; the user process will block until it gets the lock.
o Use fcntl() or flock(), but not lockf().
o Deadlock detection does not work.
o If you want to upgrade or downgrade a lock that you already hold, you must explicitly release the old lock, and then request the new one.

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Check out the 'fs messages' command for message options. You can use this to log or disable client messages.