nfs3_nra(5)nfs3_nra(5)NAMEnfs3_nra - control the number of read-ahead operations queued by the
NFS version 3 client when sequentially accessing a file
VALUES
Failsafe
Default
Allowed values
Recommended values
A warning will be issued at runtime if the tunable is set to a value
greater than 16 since this is beyond the tested limit. This is not a
serious warning but just an information message for the administrator.
DESCRIPTION
controls the number of read-ahead operations that are queued by the NFS
version 3 client when sequential access to a file is discovered. These
read-ahead operations increase concurrency and read throughput. Each
read-ahead request is generally for 32768 bytes of file data.
Who Is Expected to Change This Tunable?
The distributed file system administrator should examine this value
depending on network bandwidth and memory pressure on the client.
Restrictions on Changing
The tunable is dynamic; tuning will take effect immediately on the run‐
ning system.
When Should the Value of This Tunable Be Raised?
If the network is very high bandwidth and the client and server have
sufficient resources, increase this value to more effectively utilize
the available network bandwidth, the client resources, and the server
resources.
What Are the Side Effects of Raising the Value?
Tuning incorrectly based on network bandwidth can cause performance
problems.
When Should the Value of This Tunable Be Lowered?
In a very low bandwidth network, decrease this value so the NFS client
does not overload the network.
What Are the Side Effects of Lowering the Value?
Tuning incorrectly based on network bandwidth can cause performance
problems.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parame‐
ter may be removed or have its meaning changed in future releases of
HP-UX.
Installation of optional kernel software, from HP or other vendors, may
cause changes to tunable parameter values. After installation, some
tunable parameters may no longer be at the default or recommended val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
AUTHOR
was developed by Sun Microsystems, Inc.
SEE ALSOkctune(1M), sam(1M), gettune(2), settune(2), nfs2_nra(5), nfs4_nra(5),
values(5).
Tunable Kernel Parameters nfs3_nra(5)