Skip to main content
NetApp Knowledge Base

NFS datastores are inaccessible due to MTU mismatch

  1. Last updated
  2. Save as PDF
Views:
1,379
Visibility:
Public
Votes:
0
Category:
ontap-9
Specialty:
nas
Last Updated:

Applies to

  • NFS
  • ESXi
  • MTU
  • ONTAP 9

Issue

    • NFS datastores are mounted on ESXi servers, but attempting to read or write data hangs without error.
    • Jumbo frames (MTU 9000) are configured on ESXi or ONTAP ports.
    • Errors might be seen in EMS:

    vifmgr.cluscheck.crcerrors: Port a0a on node NodeA is reporting a high number of observed hardware errors, possibly CRC errors.
    vifmgr.cluscheck.crcerrors: Port a0a-101 on node NodeA is reporting a high number of observed hardware errors, possibly CRC errors.
    vifmgr.cluscheck.crcerrors: Port e0e on node NodeA is reporting a high number of observed hardware errors, possibly CRC errors.
    vifmgr.cluscheck.crcerrors: Port e0g on node NodeA is reporting a high number of observed hardware errors, possibly CRC errors.

    • New VMs can be created / storage vMotion VMs might be successful, but after data  transfer there is a timeout.
      • vmkernel.log: APD state is maintained intermittently.

    2021-09-28T16:12:33.376Z cpu0:2098712)WARNING: NFS: 337: Lost connection to the server 172.27.143.110 mount point /netapp_test, mounted as 8b08cbd1-435c57cd-0000-000000000000 ("netapp_test")
    2021-09-28T16:14:15.781Z cpu0:2098712)NFS: 346: Restored connection to the server 172.27.143.110 mount point /netapp_test, mounted as 8b08cbd1-435c57cd-0000-000000000000 ("netapp_test")
    2021-09-28T16:14:15.781Z cpu6:2097603)StorageApdHandler: 507: APD exit event for 0x4314ef9fec20 [8b08cbd1-435c57cd]
    2021-09-28T16:14:15.781Z cpu6:2097603)StorageApdHandlerEv: 117: Device or filesystem with identifier [8b08cbd1-435c57cd] has exited the All Paths Down state.

      • Logs will state connection fails when trying to mount new datastores.

    2024-05-15T14:20:05.123Z cpu2:2098122)NFS: 157: Unable to query remote mount point's attributes: No connection
    2024-05-15T14:20:10.456Z cpu2:2098122)WARNING: NFS: 1572: Failed to get attributes (No connection)

    • VMware support is engaged and finds nothing wrong, stating the problem is the storage device is not responding.
    • Ping from ESXi succeeds, but fails with large packet size.


    # 1. SUCCESS: Standard 64-byte packet (MTU 1500)
    [root@esxi:~] vmkping -I vmk1 10.10.10.11
    PING 10.10.10.11 (10.10.10.11): 64 data bytes
    64 bytes from 10.10.10.11: icmp_seq=0 ttl=64 time=0.421 ms
    64 bytes from 10.10.10.11: icmp_seq=1 ttl=64 time=0.385 ms

    --- 10.10.10.11 ping statistics ---
    2 packets transmitted, 2 packets received, 0% packet loss
    round-trip min/avg/max = 0.385/0.403/0.421 ms

    [root@esxi:~] vmkping -I vmk1 -s 8972 -d 10.10.10.11
    PING 10.10.10.11 (10.10.10.11): 8972 data bytes
    sendto() failed (Message too long)
    sendto() failed (Message too long)
    sendto() failed (Message too long)

    --- 10.10.10.11 ping statistics ---
    3 packets transmitted, 0 packets received, 100% packet loss

     

    Sign in to view the entire content of this KB article.

    New to NetApp?

    Learn more about our award-winning Support

    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.