Because Obsidian saves your notes as text files, you can include them in your normal backups.
If you’re not already backing up your files in general, now is the perfect time to start!
Easy directions to setup local backups: https://web.archive.org/web/20200101015933/http://www.worldbackupday.com/en/
Links about online backups: http://www.worldbackupday.com/
For remote backups on Mac I use Arq with B2 storage. My notes are included in my normal backups.
Whatever you use for backups, it’s best that it be automated. Manual backups tend to be outdated backups.