This article describes the function of the Create Rescue Agent option for Datto appliances capable of running local virtualizations.
When starting a local virtualization, you have the option to create a virtual Rescue Agent from the selected snapshot of the Source Agent and take crash-consistent backups of the VM. The feature creates a new backup agent on the Protect tab of the Datto appliance's GUI, and writes all of the Source Agent's configurations and data changes to automatic incremental snapshots. The agent will continue to back itself up until you restore the production machine or its replacement. This ensures that whenever you want to bring the original machine back into service, your data is ready and waiting.
Because the Rescue Agent creates a 'forked' backup set from the Source Agent's snapshots, the only additional space the Rescue Agent will use on your appliance will come from its incremental backups.
1. To create a virtualization with a Rescue Agent, start a local virtualization. In the Local Options screen, configure the virtualization, and check the Create Rescue Agent box, as shown in Figure 1.
2. Click Apply, followed by Start VM. You will be prompted to choose whether or not you would like to pause backups on the protected machine. Depending on your recovery scenario, click either Pause Backups or Continue Backups, and then click Confirm.
Figure 2: Pause or continue backups
3. Your virtualization will mount and begin running in the Local Virtualization screen. On the Protect tab of the Datto appliance GUI, you will see a new agent with a name comprised of the word 'rescue' and the protected server's IP address or FQDN, as shown in Figure 3. This is the Rescue Agent for your running virtualization. You can manage this agent the same way you would manage any other agent, including setting a custom backup schedule for it through the Configure Agent Settings page.
4. If the Source Agent that you created the Rescue Agent from is encrypted by the Datto appliance, the Rescue Agent will also be created as an encrypted agent. It will use the same encryption password as the Source Agent, and you will need to unseal the agent in the event of a device reboot. An example of a sealed Rescue Agent is shown in Figure 4.
5. When you no longer need the Rescue Agent, remove the protected virtualization from the Restore tab of the Datto appliance GUI by clicking Stop and then Archive.
6. When you click Archive, your Datto appliance will archive the Rescue Agent's dataset, as shown in Figure 5. This will hide the Rescue Agent in the list of Restores, stop all backups, and unmount the VM permanently. Only use this option if you have no need to initiate backups of this Rescue Agent in the future.
Figure 6: Stop and archive
7. When you no longer need the Rescue Agent's dataset, you can remove it by clicking Remove Rescue Agent on the Protect tab of the Datto device GUI. This will permanently delete any backups taken by the Rescue Agent while it was running.