Performing failover and failback operations (without Global Mirror)

In the event of a planned outage, such as a scheduled maintenance or an unplanned outage, such as a hardware failure that disables the operation of your production site, you can perform a failover operation to your recovery site to continue operations. After your production site is operational, you can perform a subsequent failback operation to move production back to its original location.

• Moving production to Site B after planned outages (failover)
  When you schedule a planned outage at your production site (Site A), you can switch production to your recovery site (Site B), allowing the processing of data to resume at Site B. This process is known as a failover recovery.
• Moving production to Site B after unplanned outages (failover)
  For this scenario, assume that an unexpected failure occurs at Site A. The failure at Site A causes the volumes to be suspended or causes a mix of suspended and full duplex volume pairs because the input might have been written to those volumes when the failure occurred.
• Returning production to Site A after planned and unplanned outages (failback)
  Returning production to its original implementation is called a failback recovery. After restoring operations at Site A, you can schedule a failback operation to synchronize data and to enable production to resume at your original site, Site A.