To fail back VMs included into a plan to a recovery location, VAO uses the following algorithm:
- The solution looks through all hosts added to the location as Compute resources to detect the first available host. This is the host where the first processed VM will be registered.
- In the list of datastores connected to the host as Storage resources, VAO searches for the first datastore that both is available and has enough capacity. This is the datastore where files of the VM will be stored.
To calculate the datastore capacity and make sure that it has enough space to accommodate the recovered VM, VAO uses the threshold that you specify when creating or configuring the location.
- VAO applies the mapping specified in the network mapping table for the location to set the required network configuration of the recovered VM.
VAO checks whether the network configuration of the detected host matches the required network configuration. If these configurations do not match, VAO goes back to step 1.
The failure of steps 1–3 for a critical VM halts the plan in the following cases:
- When VAO starts processing the next VM, the solution looks through all hosts added to the location as Compute resources to detect the next available host:
- If VAO detects such a host, this is the host where the VM will be registered.
- If there are no more available hosts, VAO uses the host detected at step 1 to register the VM.
Then VAO goes through steps 2–3 to detect the target datastore and network for the VM.
- VAO repeats step 4 for all other VMs included in the plan until all the VMs are recovered. The order in which the VMs are processed depends on the VM Recovery Options defined while configuring the plan.
If datastores added to the recovery location as Storage resources breach the capacity threshold before all the VMs are recovered, the failure of this step for a critical VM halts the plan. To troubleshoot the issue, configure the location to add more datastores and try running the halted plan again.
For more information on managing halted failover plans, see Managing Halted Plans.