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Does a Secondary System Failure Impact IO Response in Sync SnapMirror Mode?

Last Updated:

Applies to

  • ONTAP 9
  • SnapMirror


  • With synchronous SnapMirror, the secondary (destination) system is in real-time data synchronization with the primary (source) system.
  • The system is designed so that the IO response to the client is not completed until the primary system's write operations have been acknowledged by the secondary system.
  • This operation is critical for ensuring data consistency but may impact the IO response for host access depending on network latency and the performance of the secondary system.
  • Should a secondary system failure occur, Synchronous SnapMirror has mechanisms to maintain operations on the primary system without losing data integrity.
  • For instance, upon detecting a failure of the secondary system, SnapMirror can automatically fall back to asynchronous mode, restoring the primary system's IO response to standard levels.
  • The extent of IO response degradation is difficult to quantify with a general fixed value or ratio due to varying factors such as:
    • Network Latency: Greater network latency between the primary and secondary systems will affect the IO response time.
    • System Load and Resources: The resource usage and IOPS capabilities of the secondary system influence the IO response.
    • Storage Configuration: The specifics of the storage configuration, including disk types and RAID setup, also play a role in performance.

Additional Information

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