Skip to main content
NetApp Stage KB

MetroCluster SAN Host IO timeout due to power outage

Last Updated:


Applies to

  • ONTAP MetroCluster
  • Hyper-V


  • During site power outage UPS batteries fully discharged causing DR automatic switchover (AUSO) within for stretched two-node MetroCluster with SAN SVM
  • Hyper-V Host experienced IO timeout ( > 120 seconds) though switchover was within SLA
  • CIFS share access interrupted
pmcsas_admin_0: sas.port.down:debug]: SAS port "0b" went down.
pmcsas_admin_0: sas.port.down:debug]: SAS port "2a" went down.
pmcsas_asyncd_2:]: SAS adapter 2a is now online.
pmcsas_asyncd_0:]: SAS adapter 0b is now online.
fmmbx_instanceWorker: fmmb.instStat.change:info]: normal mailbox instance on DR Partner side.
stackmon_thread: stackmon.workqueue.emptied:debug]: One or more shelves have been reconciled successfully.
monitor: monitor.globalStatus.ok:notice]: The system's global status is normal.
DR_heartbeat_thread: mcc.config.auso.stDisabled:error]: The state of Automatic Unplanned Switchover capability has been disabled.
DR_heartbeat_thread: cf.fmns.readSparecore:debug]: UID of the partners sparecore disk that is being read from the partner's mailbox is 0
DR_heartbeat_thread: mcc.auso.triggered:notice]: The node has triggered an Automatic Unplanned Switchover of the DR partner. Reason: DR partner Hearbeat Lost. If Automatic Unplanned Switchover was triggered because of heartbeat loss, any ongoing dump on the partner may be aborted

Sign in to view the entire content of this KB article.

New to NetApp?

Learn more about our award-winning Support

NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.