Microsoft Azure Architect Design (AZ-304) Practice Exam & Study Guide

The preferred storage option for applications requiring high availability and REST access while also controlling costs is Read-access geo-redundant storage (RA-GRS). This storage option not only ensures that data is replicated across geographically distant regions, enhancing availability and durability, but it also provides the added benefit of read access to the secondary region. This means that if the primary region experiences a failure, applications can still access data from the secondary region, thus ensuring continuity of service.

RA-GRS is designed for scenarios where read operations are necessary even during outages, making it an optimal choice for applications that need high availability and quick recovery. Additionally, it controls costs effectively compared to some other options, as it uses standard storage rates while providing enhanced redundancy and accessibility.

In contrast, Active geo-replication in SQL Database primarily focuses on enabling failover and does not offer REST access in the same capacity as RA-GRS. Geo-redundant storage (GRS) does not provide read access to the secondary location, which can become a limitation for applications that depend on constant access to data. Azure Blob Storage with redundancy is a broader category that may include different redundancy options, but it may not specifically address the need for high availability and low cost in the same effective manner