Coming from a IT Manager at a restaurant group with very busy restaurants I can offer some insight and suggestions. Backup for POS for a long time handled as a separate service and not built in to the software. For the most part it required somebody onsite to keep an eye with enough technical skills to ensure backups are happening. As a vender you can imagine if you need to keep up with 300 site backups its a complete additional service. We relay the importance of backup, gave them simple instructions and offer referrals to companies that provide the service but most costumers didn't follow through. Of course now days POS are beginning to be built with cloud type functions so backup concerns are fading.

For your task if your backing up his POS data, the whole data set for the POS needs to be backed up. This includes the programming of the menu items, employees, departments, print routing, etc If you lose this data it is a major problem. To rebuild all the programming to get the POS functional will take at least 24 hours. To get it adjusted to its previous state will take another 30 days of little tweaks. I run all these computers on mirrored drives as realtime backup is important. This data could hold gift card information and I'm not sure what you do without it. This data cannot be backed up to the google drive in sync mode because it slows the software to the point it is unusable. I do backup the POS data set to google drive nightly with Imperlis. Imperlis will save multiple days before over writing old backups. You decide the numbr of days.

If you are backing up non POS files like employee schedules, sales reports, mainly anything you can't get from POS backoffice I use cloud drives. Its simple to setup and simple to recover. Always available from any computer. I suppose corrupt data becoming a part of your backup but it is extremely rare.