About FXOS Security Modules/Security Engine
You can use the FXOS CLI to perform the following functions on a security module/engine:
Decommission (security modules only)—Decommissioning a security module places the security module into maintenance mode. You can also decommission and then acknowledge a security module in order to correct certain fault states. See Decommissioning a Security Module.
Acknowledge—Brings newly installed security modules online. See Acknowledge a Security Module/Engine.
Power Cycle—Restarts the security module/engine. See Power-Cycling a Security Module/Engine.
Reinitialize—Reformats the security module/engine hard disk, removing all deployed applications and configurations from the security module/engine, and then restarts the system. After reinitialization is complete, if a logical device is configured for the security module/engine, the Firepower eXtensible Operating System will reinstall the application software, redeploy the logical device, and auto start the application. See Reinitializing a Security Module/Engine.
All application data on the security module/engine is deleted during reinitialization. Please back up all application data before reinitializing a security module/engine.
Power off/on—Toggles the power state for the security module/engine. See Power-Cycling a Security Module/Engine.