Skip to main content
NetApp Knowledge Base

What is the impact of modifying the nfs server option '-tcp-max-xfer-size'?

  1. Last updated
    Apr 25, 2025
  2. Save as PDF
Views:
1,565
Visibility:
Public
Votes:
2
Category:
ontap-9
Specialty:
nas
Last Updated:
4/25/2025, 12:43:51 PM

Applies to

  • ONTAP 9
  • NFS

Answer

  • There is no impact to new mount(s), will receive the max operation size of tcp-max-xfer-size
  • Existing mounts are not impacted until the client requests for this information again (normally only done on mount
  • Larger transfer sizes reduce the number of communications, which is expected to mitigate the impact of RTT.
  • It is anticipated that the number of RPC calls will be reduced, leading to a decrease in CPU load.
  • It is expected to work favorably for large files.
  • If any part of the network does not support large transfer sizes, fragmentation may occur, which can lead to increased latency.
  • In the event of a transfer error, retransmission of larger sizes may be required, resulting in an increased volume of unnecessary transmissions that negatively impact network bandwidth.
  • Performing large transfers consumes more memory or buffers.

Additional Information

ONTAP NFS transfer sizes

WARNING

  • Due to the behavior of various operating systems, NetApp does not suggest to decrease the maximum allowable transfer size on ONTAP below the value of rsize/wsize of currently mounted NFS file systems
  • This can create hangs or even data corruption with some operating systems

 

 

NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.