Skip to main content
NetApp Stage KB

Why does non-mandatory FPolicy have latency when EAGAIN is logged?

Views:
Visibility:
Public
Votes:
0
Category:
ontap-9
Specialty:
NAS
Last Updated:

Helpful 

Applies to

  • ONTAP 9
  • CIFS
  • NFS
  • FPolicy with mandatory screening set to false
  • FPolicy in asynchronous mode

Answer

  • FPolicy is guaranteed
    • The FPolicy server must acknowledge requests
    • The FPolicy server is not required to complete acknowledged requests
  • ONTAP utilizes the TCP send-buffer to queue requests
    • In asynchronous mode, file operations can be processed by ONTAP when a request is queued
    • The send-buffer is not infinite, providing a limit to the number of queued requests
    • The send-buffer can be increased from the default setting, if necessary
  • An FPolicy server that is slow to respond may cause the send-buffer to reach capacity
    • Existing requests are sent to the back of the queue via EAGAIN
    • New requests are delayed until TCP acknowledgements empty sufficient space in the send-buffer
  • Latency is experienced while the send-buffer is full
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.
4f18f049-644a-4b98-9f1d-81e0b0f1bfa8