Business Continuity and Disaster Recovery – The Storage of Data

In the scenario just discussed, where data has been corrupted or deleted, the system hosting the data remained available and accessible. In a BCDR scenario, this is not the case. Rather, you, your customer, your users, and your partners have no access to the systems hosting your data. A BCDR solution requires serious design and planning.

Many IT professionals do this kind of work as their only responsibility. This section discusses some details helpful in recovering from a disaster scenario. There will be more than enough information to clear exam questions but not enough to create a fully operational BCDR solution.

Most Azure products have built‐in capabilities for data replication, which is useful for data redundancy and recovery. Remember the Azure Storage Account redundancy options introduced in Table 1.6 in Chapter 1, “Gaining the Azure Data Engineer Associate Certification”? Are LRS and ZRS familiar without referring to that table? Those are valid ways for recovering data and data services during a datacenter/regional outage event. Those redundancy types, as you may recall, result in data being replicated multiple times in a single zone (LRS) or into all zones for the selected region (ZRS), which is synonymous with a datacenter.

This is an important point that will be covered in more detail in Chapter 8, “Keeping Data Safe and Secure,” regarding the governance and compliance concerning the physical location of your data. Consider the other storage redundancy types, such as GRS, GZRS, and their read‐only equivalents. In those scenarios data is replicated outside of the primary region, to what is called a paired region, which is usually on the same continent but not always the same country. So, if your data has restrictions on where it can be stored, this is an important consideration.