I would like to know how the data is persisted(saved) on the device, does it survive a reboot ? or a restart of the browser ?
From the author of gun:
it depends on the device. In case of the browser, localStorage is used and can survive reboot, reload, etc.
If it is in NodeJS, most storage adapters (the current default file.js, the upcoming default RAD, and others) store to disk (and even some, to S3, IPFS, etc.) which survive reboot and can even migrate between machines (like with Heroku) for the latter adapters.