Managing NFS and KRPC Kernel Configurations in HP-UX 11i v2 (Oct 2008)

Modifying the Value
Enabling this tunable provides lock cancellation interoperability between Solaris and HP-UX 11i v3
servers and HP-UX 11i v2 clients. With Solaris or HP-UX 11i v3 NFS servers, this tunable must be
enabled on HP-UX 11i v2 clients. If this tunable is not enabled, the 11i v2 NFS client could incorrectly
grab a file lock on a Solaris or HP-UX 11i v3 NFS server.
This tunable will not be available in the next release of HP-UX. Starting with the HP-UX 11i v3 release,
this behavior is enabled by default and is not user-configurable.
2.1.5 nfs_fine_grain_fs_lock
Description
When multiple threads attempt to acquire an alpha semaphore, (a filesystem lock), lock contention for
the semaphore may occur. Lock contention refers to a situation where one thread gets the lock and
other threads are forced to wait. Enabling the nfs_fine_grain_fs_lock tunable reduces the occurrence
of alpha semaphore contention in NFSv3 file operations.
Tested Values
Default: 0 (Tunable is disabled)
Min: 0
Max: 2 (Tunable is enabled)
When the tunable is disabled, file operations are performed serially, and lock contention can occur.
When the tunable is enabled, file operations are performed concurrently, and there is a reduction in
possible occurrences of alpha semaphore contention. If the tunable is set to 1, the tunable is enabled,
some file operations are performed concurrently, and there is a reduction in possible occurrences of
alpha semaphore contention. However, when the tunable is set to 2, the tunable is enabled, file
operations are performed concurrently and all alpha semaphore contention is removed from NFS
operations.
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