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SFP power below recommended value on storage

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Applies to

  • FAS/AFF systems
  • ONTAP 9
  • Fiber Channel (FC) 

Issue

  • FC link break, link flapping and/or FCP performance degradation.
  • Sysconfig -a shows the status as “link not connected” or "link disconnected "

    slot 0: Fibre Channel Target Host Adapter 0h
                    (QLogic 8324 (8362) rev. 2, <LINK NOT CONNECTED>)
                    Firmware rev:      8.9.0
                    Flash rev:         4.1.0
                    Host Port Addr:    000000
                    Connection:        No link
                    Switch Port:       Unknown   xxxx:41
                                 SFP Vendor Name:   AVAGO
                                 SFP Vendor P/N:    AFBR-57F5MZ-NA1
                                 SFP Vendor Rev:    01
                                 SFP Connector:     LC
                                 SFP Capabilities:  4, 8, 16 Gbit/Sec

  • FCP-ADAPTER.XML LOG IN ASUP shows the  Rx/Tx values for the affected port as 0.0 uWatts.

    Rx : 0.0 (uWatts)
    Tx : 0.0 (uWatts)

  • Below error recieved regarding storage LIF on NetApp:
Service: Interface FCP XXX.FC_LIF
State: CRITICAL
Time: Wed Mar 15
15:16:13 CET 2023
Description: CRIT - State: online, 8 Gbit/s (wrong speed, expected 16 Gbit/s)(!!), Address
x0:0a:09:84:80:74:xy:xx, Read: 1235654.27, Write: 9303298.57, Read OPS: 71, Write OPS: 138, Latency: 1.15 ms, Read Latency: 0.03
ms, Write Latency: 1.08ms
  • Below EMS event is logged -
    Tue Feb 27 00:20:29 +0000 [netapp: fct_tpd_work_thread_0: scsitarget.fct.sfpTxPowerLow:alert]: The SFP in FC target adapter 0f reports that it is transmitting (TX) at a low level of power. Operating value 263 (uWatts), Threshold value 317 (uWatts).

 

  • network fcp adapter show on ONTAP CLI displays low TX power:

Received Optical Power    570.7 (uWatts)
SPF Transmitted Optical Power    123.8 (uWatts)

  • Low Rx power indicates an issue upstream to the storage port, i.e defective hardware incuding cable and sfp on switch end.  This is not a problem with the SFP on storage.
  • Low Tx power indicates an issue on the storage port.
  • The below values are approximate values:

SFP Version

Light Value Ranges

Shortwave 2/4/8gb SFP Receive Power Range

Shortwave 2/4/8gb SFP Transmit Power Range

-6 dBm (250 uWatt) to -2 dBm (630 uWatt)

-6 dBm (250 uWatt) to 0 dBm (1000 uWatt)

Shortwave 4/8/16gb SFP Receive Power Range

Shortwave 4/8/16gb SFP Transmit Power Range

-5.2 dBm (300 uWatt) to 0 dBm (1000 uWatt)

-5.2 dBm (300 uWatt) to -1 dBm (790 uWatt)

Shortwave 8/16/32gb SFP Receive Power Range

Shortwave 8/16/32gb SFP Transmit Power Range

-4.6 dBm (340 uWatt) to 2 dBm (1580 uWatt)

-4.6 dBm (340 uWatt) to 2 dBm (1580 uWatt)

  • May occur in correlation:
    • Increasing error counters on switch ports
    • IO failures and/or timeouts on host OS
    • One or more failed paths from host OS
    • FC Target port on storage controller is in status <OFFLINE> or <LINK NOT CONNECTED>
    • Link resets/port resets
    • Adapter found hung errors

 

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