If you decide you want to deploy only a single Core, read this section to minimize downtime and data loss when recovering from a Core failure.

We strongly recommend that you deploy Core as an HA pair so that in an event of a failure, you can seamlessly continue operations. Core HA deployments provide a fully automated failover without end-user impact.

Configure the Core with iSCSI and use VMware HA. VMware HA is a component of the vSphere platform, which provides high availability for applications running in virtual machines. In the event of physical server failure, affected virtual machines are automatically restarted on other production servers. If you configure VMware HA for the Core, you have an automated failover for the single Core. You must be using iSCSI; do not use with Fibre Channel RDM disks.

Continually back up the Core configuration file to an external shared storage.

Restore the Core from a VM snapshot. We strongly recommend that you do not use this procedure.

The primary reason not to use this procedure is that the configuration file in the Core from the snapshot might not be current. If you made any configuration changes since the last VM snapshot, you can lose data if an incorrect Core configuration is suddenly applied to the existing Edge deployment. Using this procedure can also mean LUN snapshots triggered by the Edge might be lost. There is a configuration check performed when a Core from an old snapshot is booted up. When the Core tries to reconnect to an Edge that has a more recent configuration, an alarm is raised and the Core-Edge connection fails.