Performing failover on a mirror

Replication and Disaster Recovery Administration Guide for Hitachi NAS Platform

Part Number

Failing over is useful as a test procedure or in order to minimize disruption while production storage is under maintenance. This procedure does not apply to GAD. GAD failover is invisible to the NAS server.

Failover always involves a brief loss of service.
To fail over a mirror
  1. Unmount all file systems on the span you want to fail over.
  2. Use your storage management interface to ensure that the S-Vols contain an up-to-date copy of the data on the P-Vols. If relationships are synchronous, this means ensuring that the relationships are healthy; otherwise, it can mean running an update command or script.
  3. Use your storage management interface to promote the current S-Vols to the primary role and demote the current P-Vols to the secondary role.
  4. Run the pn all span-list command until it shows that the span is healthy again throughout the cluster.
  5. Remount the filesystems. To fail back, repeat the procedure.