NFS Client and Server Transport Connections

NFS runs over both UDP and TCP transport protocols. The default transport protocol is TCP. Using the TCP protocol increases the reliability of NFS filesystems working across WANs and ensures that the packets are successfully delivered. TCP provides congestion control and error recovery. NFS over TCP and UDP works with NFS Version 2, and Version 3.




	NOTE: TCP is the only transport protocol supported by NFS Version 4.

Supporting 1MB Transfer for TCP mounts

By default, NFS supports 32K transfer sizes across both TCP and UDP transports.

To enable support of 1MB transfers for TCP mounts, you must first modify the following tunables:

nfs3_bsize (for NFS version 3)
This tunable controls the logical block size used by NFSv3 clients. The block size represents the amount of data the client attempts to read from or write to the server during an I/O operation.
nfs4_bsize (for NFS version 4)
This tunable controls the logical block size used by NFSv4 clients. The block size represents the amount of data the client attempts to read from or write to the server during an I/O operation.

For information on the nfs3_bsize and nfs4_bsizetunables, see nfs3_bsize(1M) and nfs4_bsize(1M).

After the tunables have been modified, set the mount option for read and write size to 1MB, as follows:

mount -F nfs -o rsize=1048576, wsize=1048576

Changes to the NFS Server Daemon

The NFS server daemon (nfsd) handles client filesystem requests. By default, nfsd starts over TCP and UDP for NFSv2 and NFSv3. If NFSv4 is enabled, the nfsd daemon is started to service all TCP and UDP requests.

If you want to change startup parameters for nfsd, you must login as superuser (root) and make changes to the /etc/default/nfs file or use the setoncenv command.

The /etc/default/nfs file provides startup parameters for the nfsd daemon and rpc.lockd daemon. For more information on the /etc/default/nfs file, see nfs(1M).

The setoncenv command initializes, displays, and removes the value of NFS configuration variables, found in either of the following files:

/etc/rc.config.d/nfsconf
/etc/rc.config.d/namesvrs
/etc/default/autofs
/etc/default/key
/etc/default/nfs
/etc/default/nfslogd

For more information on the setoncenvcommand, see setoncenv(1M).

NFS Client and Server Transport Connections

Technical documentation

» Table of Contents

» Index

Supporting 1MB Transfer for TCP mounts

Changes to the NFS Server Daemon