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How to Handle watchdog resets (WDR)

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Applies to

  • ONTAP 9
  • All FAS/AFF systems
  • Watchdog reset reboot events
  • HA Group Notification from node (REBOOT (panic)) ALERT
    • PANIC  : watchdog nmi on cpu
  • HA Group Notification (REBOOT (watchdog reset)) ALERT

Description

What is a watchdog reset?

A watchdog is an independent timer that monitors the progress of the main controller running ONTAP.

  • Its function is to serve as an automatic server restart in the event the system encounters an unrecoverable system error.
  • The watchdog implemented by NetApp uses a two-level timer with different actions associated with each level of time.
  • The Level 1/Level 2 Watchdog operation is not proprietary to NetApp and is used throughout the hardware industry.

 

Level Type Description
Level 1: Timeout

The storage appliance attempts to panic and dump the core in response to a non-maskable interrupt.

  • An L1 watchdog is issued if the timer is not reset within 1.5 seconds.
  • Once an L1 watchdog is successfully issued, the system returns to service and a core file is written, allowing NetApp to determine the root cause of the hang. 
Level 2: Reset

The storage appliance resets through a hard reset signal sent from the timer. 

  • An L2 watchdog is issued if the watchdog timer is not reset within two seconds after the L1 watchdog. 
  • The L2 watchdog does not generate a Core dump.
  • It is not necessary to ‘recover’ from a watchdog timeout or watchdog reset, as both of these events are recovery mechanisms for other failures.
    • The objective instead is to identify the failure(s) that caused the watchdog event.
How to Identify a Watchdog NMI Panic

event log show -severity * -message-name panic*

  • Up Node that performed Takeover

Fri Nov 18 01:20:54 -0600 [NetApp01: cf_main: cf.fsm.takeover.panic:alert]: Failover monitor: takeover attempted after partner panic.
Fri Nov 18 01:21:37 -0600 [NetApp01: cf_main: callhome.sfo.takeover.panic:EMERGENCY]: Call home for CONTROLLER TAKEOVER COMPLETE PANIC

  • Partner node, following reboot

Fri Nov 18 01:42:35 -0600 [NetApp02: splog_main: mgr.stack.string:notice]: Panic string: watchdog nmi on cpu 3, hang cpu is 0 in SK process wafl_scan_exempt on release 9.9.1P7 (C)

Platform Article

FAS8020 / FAS8040 / FAS8060 / FAS8080 / AFF8020 / AFF8040 / AFF8060 / AFF8080

Handling L2 Watchdog Resets on the FAS8020 / FAS8040 / FAS8060 / FAS8080 / AFF8020 / AFF8040 / AFF8060 / AFF8080

FAS2520 / FAS2552 / FAS2554

Handling L2 Watchdog Resets on the FAS2520 / FAS2552 / FAS2554
AFF A700 / FAS9000 Handling L2 Watchdog Resets on the AFF A700 and FAS9000 platforms

FAS2620 / FAS2650 / AFF A200

Handling L2 Watchdog Resets on the FAS2620 / FAS2650 / AFF A200

AFF A220 / AFF A150 / AFF C190 / FAS2750 / FAS2720

Handling L2 Watchdog Resets on the AFF A220 / AFF A150 / AFF C190 / FAS2750 / FAS2720

AFF A400 / AFF C400 / FAS8700 / FAS8300

Handling L2 Watchdog Resets on the AFF A400 / AFF C400 / FAS8700 / FAS8300
AFF A700s Handling L2 Watchdog Resets on the AFF A700s Platform
AFF A300 / FAS8200 Handling L2 Watchdog Resets on the FAS8200 and AFF A300 platforms

AFF A800 / AFF C800

Handling L2 Watchdog Resets on the AFF A800 and AFF C800 Platform
AFF A320 Handling L2 Watchdog Resets on the AFF A320 Platform
AFF A900 / FAS9500 Handling L2 Watchdog Resets on the AFF A900 and FAS9500 Platform
AFF A250 / FAS500f / AFF C250 Handling L2 Watchdog Resets on the AFF A250 / FAS500f / AFF C250
FAS3250 Handling L2 Watchdog Resets on the FAS3250

Additional Information

For further assistance, contact NetApp Technical Support and reference this article along with the data collected.

 

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