Mission critical application VMs should be in an availability set with OS disks for each coming from 2 different storage accounts so that a connectivity loss to storage does not impact both machines.
Same can be achieved with use managed disk option while provisioning azure VMs.
Use managed disks across machines in an availability set so that the headache of choosing and managing storage accounts (and consequently getting into this situation) is avoided.
Example: – let’s say you have an application running on five VMs, and the VMs are in an Availability Set. The disks for those VMs won’t all be stored in the same stamp, so if one stamp goes down, the other instances of the application continue to run.