You have an Azure subscription for used for testing and development purposes only. The subscription contains Azure virtual machines that unmanaged, standard hard disk drives (HDD).
You need to recommend a recovery strategy for the virtual machines if an Azure region fails for a sustained period. The recovery time objective (RTO) can be up to seven days. The solution must minimize costs.
What should you include in the recommendation?
Geo-redundant storage (GRS) is designed to provide at least 99.99999999999999% (16 9's) durability of objects over a given year by replicating your data to a secondary region that is hundreds of miles away from the primary region. If your storage account has GRS enabled, then your data is durable even in the case of a complete regional outage or a disaster in which the primary region isn't recoverable.
GRS replicates your data to another data center in a secondary region, but that data is available to be read only if Microsoft initiates a failover from the primary to secondary region.
If a datacenter-level disaster (for example, fire or flooding) occurs, all replicas in a storage account using LRS may be lost or unrecoverable. To mitigate this risk, Microsoft recommends using zone-redundant storage (ZRS), geo-redundant storage (GRS), or geo-zone-redundant storage (GZRS).