Skip to main content
NetApp Knowledge Base

Link break detected on Fibre Channel target connected to Brocade switch due to faulty storage end sfp

Views:
41
Visibility:
Public
Votes:
0
Category:
ontap-9
Specialty:
san
Last Updated:

Applies to

  • ONTAP 9
  • FCP
  • Brocade Switch

Issue

  • EMS log on NetApp end reports a link reset event, where the link went down and came back up within 5 seconds.

Wed Feb 14 14:52:15 +0530 [NetApp1: fct_tpd_work_thread_0: scsitarget.slifct.linkBreak:error]: Link break detected on Fibre Channel target HBA 2c with event status 1 , topology type 1, status1 0x0, status2 0x0.
Wed Feb 14 14:52:20 +0530 [NetApp1: fct_tpd_work_thread_0: scsitarget.hwpfct.linkUp:notice]: Link up on Fibre Channel target adapter 2c.

Fibre Channel Target Adapter 2c
Received Optical Power - 996.9 (uWatts)
SFP Transmitted Optical Power - 992.0 (uWatts)

  • There are no other FCP events reported on the storage end around the issue time.
  • The connected switch port does not report any errors reported under porterrshow output-

/fabos/cliexec/porterrshow :
          frames        enc     crc     crc     too     too     bad     enc    disc    link    loss    loss    frjt    fbsy     c3timeout     pcs      uncor
        tx       rx      in     err     g_eof   shrt    long    eof     out    c3      fail    sync    sig                      tx      rx      err     err
75:  242.2k  398.3k    0       0       0       0       0       0       0       0       0       0       0       0       0       0       0       0       0

 

  • The state of the switch port is up and online.

/fabos/bin/switchshow :
Index Slot Port Address Media  Speed        State    Proto
============================================================
75    9   11   654bxx   id    N32   Online      FC  F-Port  1 N Port + 1 NPIV public

 

  • Errdump does not have any such erroneous events reported during the issue time.
  • Fabriclog output shows the switch port connected to the affected storage port encountered a reset.

Switch 0; Wed Feb 14 14:51:40 2024 IST (GMT+5:30)
14:51:40.025111 SCN Port Offline;rsn=0x2,g=0x6a             D0,P0  D0,P0  75    NA
14:51:40.025118 *Removing all nodes from port               D0,P0  D0,P0  75    NA
14:51:44.795477 SCN LR_PORT(0);g=0x6a                       D0,P0  D0,P0  75    NA
14:51:44.858285 SCN Port Online; g=0x6a,isolated=0          D0,P0  D0,P1  75    NA
14:51:44.858365 Port Elp engaged                            D0,P1  D0,P0  75    NA
14:51:44.858377 *Removing all nodes from port               D0,P0  D0,P0  75    NA
14:51:44.858608 SCN Port F_PORT                             D0,P1  D0,P0  75    NA
14:51:44.968592 SCN LR_PORT(0);g=0x6a LR_IN                 D0,P0  D0,P0  75    NA

 

  • Sfp Tx power looks very good on the switch end, which tells us that the switch sfp is in a good condition.
  • The Rx power is very low ((572.5uW)compared to the Tx power (1238.9 uW) on the switch end.

=============
Slot  9/Port 11:
=============
RX Power:    -2.4    dBm (572.5uW)
TX Power:    0.9     dBm (1238.9 uW)

  • Whereas, the storage end Tx power is SFP Transmitted Optical Power - 992.0 (uWatts)
  • This tells us that the issue lies somewhere upstream to the switch, which could be the cable or end device sfp ( NetApp storage in this scenario).

 

  • Cable testing needs to be performed to further isolate if the issue is faulty cable.
  • If the cable is good, then sfp on end device connected to switch has to be swapped.

 

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.