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

Restrictions on Changing
The nfs3_jukebox_delay tunable is dynamic. System reboot is not required to activate changes made
to this tunable. Only NFSv3 mount points are affected when you change the value of this tunable.
Modifying the Value
If it takes a considerable amount of time for files to migrate from your HSM storage devices, increase
the value of this tunable. However, if you increase the value of the tunable, it can prevent the file from
becoming immediately visible when it becomes available.
If files are migrated quickly from your HSM storage devices, decrease the value of this tunable. If you
decrease the value of the tunable, you can view the file as soon as it becomes available. However, if
you set the tunable too low, your client can send retransmissions before the server is able to retrieve
the files from the HSM storage devices.
2.1.25 nfs3_lookup_neg_cache
Description
The nfs3_lookup_neg_cache tunable controls whether a negative name cache is used for NFSv3
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 nfs4_lookup_neg_cache tunable controls whether a negative name cache is
used for NFSv4 mounted filesystems. For more information on these tunables, see:
• nfs2_lookup_neg_cache
• nfs4_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 nfs3_lookup_neg_cache tunable is dynamic. System reboot is not required to activate changes
made to this tunable. Only NFSv3 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 filesystem changes 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.
2.1.26 nfs3_max_async_directio_requests
Description
The nfs3_max_async_directio_requests tunable specifies the maximum number of parallel read or
write requests that NFS v3 direct can send on behalf of the application. This tunable is effective only
on processes performing I/O operation on the forcedirectio NFS mount point.
Tested Values
Default: 8
Min: 4
Max: 64