Modifying the NFSv3 and NFSv4 TCP maximum transfer size

You can modify the -tcp-max-xfer-size option to configure maximum transfer sizes for all TCP connections using the NFSv3 and NFSv4.x protocols.

About this task

You can modify these options individually for each storage virtual machine (SVM).

Beginning in ONTAP 9, the v3-tcp-max-read-size and v3-tcp-max-write-size options are obsolete. You must use the -tcp-max-xfer-size option instead.


  1. Set the privilege level to advanced: set -privilege advanced
  2. Perform one of the following actions:
    If you want to... Enter the command...
    Modify the NFSv3 or NFSv4 TCP maximum transfer size vserver nfs modify -vserver vserver_name -tcp-max-xfer-size integer_max_xfer_size
    Option Range Default
    -tcp-max-xfer-size 8192 to 1048576 bytes 65536 bytes
    Note: The maximum transfer size that you enter must be a multiple of 4 KB (4096 bytes). Requests that are not properly aligned negatively affect performance.
  3. Use the vserver nfs show -fields tcp-max-xfer-size command to verify the changes.
  4. If any clients use static mounts, unmount and remount for the new parameter size to take effect.


The following command sets the NFSv3 and NFSv4.x TCP maximum transfer size to 1048576 bytes on the SVM named vs1:
vs1::> vserver nfs modify -vserver vs1 -tcp-max-xfer-size 1048576