The startup configuration resides in the /var/config/vcs/scripts directory.
When you boot up a device for the first time, the default configuration is the running configuration. As you configure the device, the changes are written to the running configuration. To save the changes as the startup configuration, you must copy the currently effective configuration (the running configuration) as the startup configuration. Changes to the running configuration persist when the device reboots.
Default configuration files are part of the firmware package for the device and are automatically applied to the startup configuration under the following conditions:
You cannot remove, rename, or change the default configuration.
The startup configuration is persistent. It is applied when the system reboots.
The startup configuration file name is startup-config.
The configuration currently effective on the device is referred to as the running configuration. Any configuration change you make while the device is online are made to the running configuration.
The running configuration file name is running-config.