Managing NFS and KRPC Kernel Configurations in HP-UX 11i v3 (762807-001, March 2014)

Tested Values
Modifying the Value
Enable this tunable to cache the contents of symbolic links. Because the client uses the cached version,
changes made to the contents of the symbolic link file are not immediately visible to applications
running on the client.
To make the changes made to the symbolic link file immediately visible to applications on the client,
disable this tunable. Disabling the tunable can result in more over-the-wire requests from the client if
filesystems are mounted with NFSv4 and contain symbolic links.
2.1.37 nfs4_lookup_neg_cache
Description
The nfs4_lookup_neg_cache tunable controls whether a negative name cache is used for NFSv4
mounted filesystems. The negative name cache records file names that were looked up but not found.
This cache helps avoid over-the-wire lookups for files that are already known to be non-existent.
The nfs2_lookup_neg_cache tunable controls whether a negative name cache is used for NFSv2
mounted filesystems. The nfs3_lookup_neg_cache tunable controls whether a negative name cache is
used for NFSv3 mounted filesystems. For more information on these tunables, see:
• nfs2_lookup_neg_cache
• nfs3_lookup_neg_cache
Tested Values
Default: 1 (Negative name cache will be used)
Min: 0 (Negative name cache will not be used)
Max: 1
Restrictions on Changing
The nfs4_lookup_neg_cache tunable is dynamic. System reboot is not required to activate changes
made to this tunable. Only NFSv4 mount points are affected by changing the value of this tunable.
Modifying the Value
If filesystems are mounted read-only on the client, and applications running on the client need to
immediately see any filesystem changes made on the server, disable this tunable. If you disable this
tunable, also consider disabling the nfs_disable_rddir_cache tunable. For more information, see
nfs_disable_rddir_cache.
2.1.38 nfs4_max_threads
Description
The nfs4_max_threads tunable controls the number of kernel threads that perform asynchronous I/O
for NFSv4 filesystems. The operations executed asynchronously are read, readdir, and write.
The nfs2_max_threads tunable controls the number of kernel threads that perform asynchronous I/O
for NFSv2 filesystems. The nfs3_max_threads tunable controls the number of kernel threads that
perform asynchronous I/O for NFSv3 filesystems. For more information on these tunables, see:
• nfs2_max_threads
• nfs3_max_threads