NFS Services Administrator's Guide (762805-001, March 2014)

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.
• nfs3_max_transfer_size (for NFS version 3)
This tunable specifies the maximum size of the data portion of NFSv3 READ, WRITE, READDIR,
and READDIRPLUS requests. This parameter controls both the maximum size of the data that
the server returns and the maximum size of the request the client generates.
• nfs4_max_transfer_size (for NFS version 4)
This tunable specifies the maximum size of the data portion of NFSv4 READ, WRITE, READDIR,
and READDIRPLUS requests. This parameter controls both the maximum size of the data that
the server returns and the maximum size of the request the client generates.
• nfs3_max_transfer_size_cots (for NFS version 3)
This tunable specifies the maximum size of the data portion of NFSv3 READ, WRITE, READDIR,
and READDIRPLUS requests. This parameter controls both the maximum size of the data the
server returns as well as the maximum size of the request the client generates over a
connection-oriented transport, such as TCP.
• nfs4_max_transfer_size_cots (for NFS version 4)
This tunable specifies the maximum size of the data portion of NFSv4 READ, WRITE, READDIR,
and READDIRPLUS requests. This parameter controls both the maximum size of the data the
server returns as well as the maximum size of the request the client generates over a
connection-oriented transport, such as TCP.
For information on the nfs3_bsize and nfs4_bsize tunables, 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).
42 Configuring and administering NFS services