nfs4_max_transfer_size_cots(5) File Formats Manual nfs4_max_transfer_size_cots(5)
NAME
nfs4_max_transfer_size_cots - controls the data portion size of a NFS version 4 read, write, readdir, or readdirplus request over TCP
VALUES
Failsafe
Default
Allowed values
Recommended values
A warning will be issued at runtime if the tunable is set to a value greater than 1048576 since this is outside the tested limits. This is
not a serious warning but just an information message for the administrator.
DESCRIPTION
controls the maximum size of the data portion of a NFS version 4 read, write, readdir, or readdirplus request over TCP. This parameter con-
trols both the maximum size of a request that the server returns as well as the maximum size of a request that the client generates.
Who Is Expected to Change This Tunable?
Distributed file system administrators should examine this value if they want to decrease or increase the default size of a NFS version 4
packet over TCP.
Restrictions on Changing
The tunable is dynamic; however, the transfer size for a file system is set when the file system is mounted. To affect a particular file
system, unmount and mount the file system after changing this parameter.
The actual NFS version 4 transfer size over TCP is controlled by these tunable parameters: and The actual transfer size will depend on the
tune with the smallest value. For NFS TCP traffic you should increase and to the same value to increase the transfer size. To decrease the
transfer size, just changing is sufficient.
When Should the Value of This Tunable Be Raised?
An increase in the transfer size will result in fewer requests to the NFS server at the expense of system resources on both the NFS client
and NFS server.
What Are the Side Effects of Raising the Value?
Setting the limit large causes more system resources to be consumed by both the NFS client and NFS server.
When Should the Value of This Tunable Be Lowered?
In the event of NFS communication failures, the value should be changed back to the default value.
What Are the Side Effects of Lowering the Value?
An increase in NFS version 4 network traffic over TCP caused by an increase in the number of I/O requests.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter 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 values. For information about the effects of installation on tun-
able values, 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 ALSO
kctune(1M), sam(1M), gettune(2), settune(2), nfs4_bsize(5), nfs4_max_transfer_size(5), values(5).
Tunable Kernel Parameters nfs4_max_transfer_size_cots(5)