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What's cf_hwassist_missedKeepAlive timeout and tolerant period?

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fas-systems
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hw
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Applies to

  • NetApp AFF and FAS systems
  • ONTAP 9

Answer

  • cf_hwassist_missedKeepAlive incident is recorded in EMS after 60 seconds, after a hw-assist packet sent
  • The hw-assist packets are sent by UDP every 180 seconds:
    •  There is no retransmission of packets if the packets are sent and not received
    • If a UDP packet is dropped, blocked, wedged, redirected, etc.. and a node doesn't receive it, the node will just wait for 180 seconds, until the next packet is sent
  • So if a cf_hwassist_recvKeepAlive event is showing within 120 seconds after cf_hwassist_missedKeepAlive, it can be ignored safely

[Nodename-02: cf_hwassist: cf.hwassist.missedKeepAlive:debug]: HW-assisted takeover missing keep-alive messages from HA partner (Nodename-01).
[Nodename-02: cf_hwassist: cf.hwassist.recvKeepAlive:debug]: hw_assist: Received hw_assist KeepAlive alert from partner(Nodename-01).

Additional Information

  • For the cause of cf_hwassist_missedKeepAlive, because hw-assist configured and transmit with IP and port on e0M which goes through customer network environment, nearly every instance of this type of failure, is due to network dropped packets.
  • Check the hwassist-health-check-interval by command

aff200-2n-dal-1::> storage failover show -fields hwassist,hwassist-partner-ip,hwassist-partner-port,hwassist-health-check-interval,hwassist-retry-count,hwassist-status
node          hwassist hwassist-partner-ip hwassist-partner-port hwassist-health-check-interval hwassist-retry-count hwassist-status
------------- -------- ------------------- --------------------- ------------------------------ -------------------- ---------------
aff200-dal-1a true     10.128.227.184      4444                  180                            2                    active
aff200-dal-1b true     10.128.227.183      4444                  180                            2                    active
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