# boot subsystem

#### Syntax

boot [ backup ] subsystem subsysName relFileName

no boot [ backup ] subsystem [ subsysName ]

#### Release Information

Command introduced before JunosE Release 7.1.0.

#### Description

Configures the selected subsystem to use the specified release the next time the subsystem is booted. The no version disables the subsystem. The backup option enables you to specify a backup release for the module in the specified slot in case the module reboots more times than allowed within the period specified by the boot revert-tolerance command.

#### Options

- backup—Configures a backup setting
- subsysName—Name of the subsystem to be configured
- relFileName—Name of system software file to use

#### Mode

Global Configuration