If I brought a physical copy of ACNL, how should I backup my save data?

[Akeea]

I recently did a post in this about my R button on my 3DS being stuck(which can seen on this link: http://www.belltreeforums.com/showthread.php?268371-R-button-on-my-3DS-got-stuck), and I'm about to send to Nintendo for repair. Now I'm worried about my save file for acnl getting lost, and so I was wondering is there a way to back those files, or is actual save file saved on the cartridge itself?

 

[FireNinja1]

The save is on the cart. The only thing you miiiight lose are the Street and SpotPass houses, but don't worry about everything else. Keep the cart and you'll be fine.

 

[Greninja]

Nvm

 

[Akeea]

Thanks! I thought that my acnl save file was saved to sd card, and I sold my old 3ds and cartridge online, and when I brought another 3ds as well as another copy of acnl, I couldn't find my save file, so I had to start all over again. . Thank You for the clarification.

 

[stitchmaker]

The spot pass houses will go to another 3DS. I changed my main town cartridge to a different 3DS.
All my spot pass houses were there. Your dream address will change.

 

[Silas James Reel]

Your dream address will change, nothing more. No biggie I'm assuming.