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How to obtain a sync core from a hanging / unresponsive storage system

Last Updated:

Applies to

  •   Data ONTAP 7 and earlier    
  •   Data ONTAP 8.1 7-Mode    
  •   Data ONTAP 8.2 7-Mode    
  •   Data ONTAP 8 7-Mode 


This article describes the procedure that should be followed to obtain a sync core from a hanging/unresponsive storage system.

Note: To proceed with this action requires NetApp Technical Support Engineer guidelines on how to proceed.

The term 'sync core' is a remnant from older versions of Data ONTAP that required that the 'sync' command line utility be manually issued to flush the core to disk. Perhaps a more accurate term for this process would be 'user-generated core'.
A user-generated core is triggered by sending a Non-Maskable Interrupt (NMI) broadcast to all CPUs on the system. The system immediately panics and will be taken over immediately by the partner if the 'cf.takeover.on_panic' is set to on. If this option is set to off, takeover will be deferred until the core file is written to disk.
Note: The takeover process takes less time for a panic than for an operator issued takeover because the taken over system is not shut down.

Also, note that there are several different methods of initiating a user-generated core depending upon which NetApp storage system model you have.
A user-generated core should only be initiated at the direction of NetApp technical support and requires additional details about the reasons for forcing a panic than required for a system-generated panic because the cause of the panic is not explicitly given as with a system generated panic.
Platform-specific instructions will be provided within the context of the technical case.



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