More or less it depends on the service provider you have chosen. I'm not talking specifically about any provider but a Generic Storage as a service provider.So I'm taking this question as a whole what if my files gets lost in Cloud. And I'm considering two scenarios: The provider goes out of business/Provider himself loses your file out of hardware failure.Going out of business is a bit vague idea. Even if they go out of business then at least they will pryou a prior intimation that users can recover their data as we are going to shut down this service. This should be there in your SLA (Service Level Agreement). They never go out of business in one day. If they foresee it they'll intimate you.Hardware failure is something which needs to be taken care of. It's a bitter truth but it is what it is. Hardware does fail and one can easily lose data. So the redundancy which others have talked about in other answers is something which you provider also takes care of.Redundancy is increased usually by isolating the hardware. Isolation in a way that the hardware is totally isolated in form of Network/Power. And this redundancy not only saves one from hardware failure but maintenance windows as well. So it depends who will pay for this redundancy. It could be your service provider who will eventually keep replicating your data on to the other hardware and would make it look like one. Or the provider will give you this choice in form of Availability Areas/Zones. So that when you store your data on ZoneA do replicate it on Zone B as well. And for some reasons if hardware goes down on A you would still be left with data on B.