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Low RX observed on NetApp FC target port and switch port due to faulty cable

  1. Last updated
    Oct 3, 2024
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Category:
fas-systems
Specialty:
san
Last Updated:
10/3/2024, 6:58:45 PM

Applies to

  • ONTAP
  • FC
  • Brocade switch

Issue

  • Lost access to volume error message is observed on host end.

Lost access to volume due to connectivity issues. Recovery attempt is in progress and the outcome will be reported shortly.

  • FC port on NetApp storage is online and shows low RX value.

NetApp::> fcp adapter show -instance -node NetApp-02 -adapter 0e
  (network fcp adaptershow)
        Received Optical Power: 91.7(uWatts)
    Is Received PowerIn Range: true
 SFP TransmittedOptical Power: 554.6 (uWatts)

  • Below STIO errors along with sfpRxPowerLow are reported  in EMS logs on storage end

Wed Dec 27 00:08:46 +0000 [NetApp-02:fct_tpd_work_thread_0: fcp.io.status:debug]: STIO Adapter:0e AEN 0x8048 (RECV_ERROR)MboxStatus1 0xfffe MboxStatus2 0x1
Wed Dec 27 00:11:30 +0000 [NetApp-02:fct_tpd_work_thread_0: fcp.io.status:debug]: STIO Adapter:0e AEN 0x8048 (RECV_ERROR)MboxStatus1 0xfffe MboxStatus2 0x1

Thu Aug 29 00:16:36 +0530 [NetApp: fct_tpd_work_thread_0: scsitarget.fct.sfpRxPowerLow:alert]: The SFP in FC target adapter 2c reports that it is receiving (RX) at a low level of power. Operating value 12 (uWatts), Threshold value 15 (uWatts).
Thu Aug 29 06:02:25 +0530 [NetApp: fct_tpd_work_thread_0: fcp.io.status:debug]: STIO Adapter:2c AEN 0x8048 (RECV_ERROR) MboxStatus1 0x1011 MboxStatus2 0xc1
 

  • sfpshow indicates Low Rx on Brocade switch port which is connected to FC target port.

sfpshow 1/19
[..]
RXPower:    -9.1    dBm (121.9uW)
TXPower:    -3.0    dBm (506.7 uW)

  • crc error, disc c3, c3 timeout tx errors observed in porterrshow output.

switch:admin> porterrshow 0
           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
  0:   22.0m 16.0m   0      3.6k  3.6k   0      0    69      0      1.0k  0      0      0     0      0      1.0k  0      0      0

 

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