Does NVRAM Contain All Settings Or Only Those Changed From Default?

[HarryMuscle]

I'm doing a bit of research on backing up and restoring settings on Asus routers and I was wondering if anyone knows whether NVRAM variables contain all router settings, or only those that have been changed from default? Or in other words, if a NVRAM variable doesn't exist on the router will the GUI just use a default value for the missing NVRAM variable or will it panic and do unpredictable things?

Thanks,
Harry

P.S. I'm thinking of using this app to backup, move, and restore settings between various routers: https://www.medo64.com/wrtsettings

 

[L&LD]

They should contain almost all, in addition to the JFFS partition too.

The GUI doesn't do anything, such as overriding or using a default value. The firmware controls both. And the firmware relies on the NVRAM and JFFS partitions (along with other hidden areas) to do so.

 

[ColinTaylor]

P.S. I'm thinking of using this app to backup, move, and restore settings between various routers: https://www.medo64.com/wrtsettings

The nvram backup file is not transferable to other routers. You said you had been researching backup/restores so I'm sure you're already aware of this.

To directly answer the question in your title, the nvram backup file contains a copy of all nvram variables not just those that have been changed.

 

[HarryMuscle]

The nvram backup file is not transferable to other routers. You said you had been researching backup/restores so I'm sure you're already aware of this.

To directly answer the question in your title, the nvram backup file contains a copy of all nvram variables not just those that have been changed.

Thanks. I was hoping the NVRAM only contained changed settings in which case I could have used the tool I linked to in my original post to "massage" the data and load it onto other routers.

Thanks,
Harry

 

[RMerlin]

Thanks. I was hoping the NVRAM only contained changed settings in which case I could have used the tool I linked to in my original post to "massage" the data and load it onto other routers.

Thanks,
Harry

My advice is to focus only on settings that are more work to reconfigure manually, like the content of dhcp_staticlist for example. These can quickly be re-created by copy/pasting values over SSH.

The following command should give you a sorted, readable list of settings for you to browse through:

nvram show | sort