The article explains the difference of load override and load update option for loading a configuration from a file or the terminal.
user@router# load ?
Possible completions:
factory-default Override existing configuration with factory default
merge Merge contents with existing configuration
override Override existing configuration
patch Load patch file into configuration
replace Replace configuration data
set Execute set of commands on existing configuration
update Update existing configuration
What's the difference of load override and load update option for loading a configuration from a file or the terminal.
Discards the current candidate configuration. Loads either the configuration in the filename that you specify or the configuration that you type at the terminal. When you use the override option and commit the configuration, all system processes reparse the configuration. You can use the override option at any level of the hierarchy.
To replace only those parts of the configuration that have changed, you specify the update option at any level of the hierarchy. The load update operation compares the candidate configuration and the new configuration data. This operation changes only those parts of the candidate configuration that are different from the new configuration. You would use this operation, for example, if there is an existing BGP configuration and the file you are loading changes it in some way.
Refer to Loading Configuration Files for the full information.