Microsoft Azure Fundamentals AZ-900 Practice Exam 2025 – Complete Study Resource

The most cost-effective way to store rarely used data is through archival storage. Archival storage solutions are specifically designed for data that is infrequently accessed, offering a lower-cost option compared to more active storage tiers. This is ideal for long-term retention of data that does not need to be readily available but must be kept for compliance or historical purposes.

Typically, archival storage uses less expensive media and typically has longer access times, making it suitable for data that isn't expected to be retrieved frequently. This approach minimizes costs while ensuring that the data remains secure and accessible when needed, albeit after some delays in retrieval.

In contrast, other storage options, such as hot and warm storage, are tailored for more frequently accessed data, thus incurring higher costs for storage, data retrieval, and performance. These options are suitable for active workloads or data that requires quick access, which isn't aligned with the needs of rarely used data.