I think it's very important to save a config of a good setup. Firstly it's a great reference if you ever need to go back and refer to things, secondly it's a great way to show what you did was actually correct and that you did configure things correctly from the start (especially for me as a consultant!).

There is a handy tool provided within OnTap (and you get this functionality from Operations Manager also) to do entire config dumps, compares and restores. This is limited to the filers base configuration and doesn't necessarily include areas like volume setup or various config files within "/etc".

b2net-filer01> config
Usage:
        config clone <filer> <remote_user>
        config diff [-o <output_file>] <config_file1> [ <config_file2> ]
        config dump [-f] [-v] <config_file>
        config restore [-v] <config_file>

The command is very simple and straight forward. You start by dumping out the configuration from the filer. This automatically goes into /etc/configs. From here you can then clone the config if needed, or compare (diff) the config. Running diff is a very good way of comparing a config between 2 points in time, if you aren't sure what has changed, or if you are comparing a filer upgrade and you copy the config files between the 2 systems or if you want to have primary and DR as identical as possible. And finally you can also use the restore feature, although I have personally never used it, and I'm not sure what other changes would need to be made within the /etc folder to do a system restore (potentially I guess you could also do a snap restore on vol0 or copy across a backup vol0).

Overall a very useful command. I use this most for taking backups of filer configs and comparing them between similar systems (for instance primary and DR), or even comparing configs over time.