We are thinking about moving our virtual machines (Hyper-V VHDs) to Windows Azure but I haven't found much about what kind of fault tolerance that infrastructure provides. When I run VHD in Azure, I've got two questions:

1. Is my VHD and all the data in it safe? I think that uploaded VHDs use the "Storage" infrastructure so they should be automatically replicated to multiple disks and geographically distributed but should I still make a full-image backup just to be safe? (Note that of course I will be backing up the actual data inside VMs that I care about; I just want to know if there is a chance greater than 0.0000001% that one day I will receive an email from Microsoft telling me that my VM is gone and that I should create or restore it from scratch).

2. Do I need to worry about other things regarding the availability of my VMs? I mean, when I have an on-premise server I need to worry about the hardware itself, about the host operating system, what would happen if my router failed, if my Hyper-V's C: drive failed etc. Am I right in thinking that with Azure, their infrastructure takes care of all of this?

Thanks.