NFS Services Administrator's Guide (B.11.31.03) August 2008

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
58 Configuring and Administering NFS Services