[sschueller]

This is not that hard. Each store can keep a local record of what is going on. Back in the "dark ages" this was done anyway, credit card transactions were settled at the end of the day. Inventory at a physical location can be tracked locally and updates sent to a central system later to figure out what needs to be restocked where.

Unlike other distributed databases you don't have one store selling an item of food from another store (especially if your online system is down) and need to do a split brain recomp.

[OskarS]

Enough people rely on debit cards nowadays that only work online that it would still cause significant disruption. Enough that it's probably not worth keeping the stores open until it can be fixed.

[londons_explore]

Many card machines can work 'online' but not using the stores own servers.

[guerrilla]

I don't even know a single person with a credit card here. Everything is done with debit cards which require being online to check the balance and reject the transaction if it's insufficient.