A company is developing a new application that will store user-generated content, including photos and short videos. These files will be uploaded frequently and need to be immediately available for viewing by other users. The application also requires a robust mechanism for handling eventual consistency across multiple regions, ensuring data integrity even if a region becomes temporarily unavailable. Which Azure Blob Storage replication strategy best meets these requirements?
- ALocally Redundant Storage (LRS)
- BZone-Redundant Storage (ZRS)
- CGeo-Redundant Storage (GRS)
- DRead-Access Geo-Redundant Storage (RA-GRS)
Show answer & explanationAnswer & explanation
Correct answer: D. Read-Access Geo-Redundant Storage (RA-GRS)
RA-GRS provides geo-redundancy (data replicated to a secondary region) and allows read access to the data in the secondary region. This ensures high availability and data integrity even if the primary region fails. While GRS also provides geo-redundancy, RA-GRS explicitly allows reads from the secondary, making it suitable for scenarios where data needs to be immediately viewable and eventually consistent across regions during failovers.
Why the other options are wrong
- A. LRS provides local redundancy within a single data center, which does not protect against regional outages or provide cross-region availability.
- B. ZRS provides redundancy across availability zones within a single region, offering better resilience than LRS but still not protecting against a full regional outage or providing cross-region access.
- C. GRS replicates data to a secondary region, but read access to the secondary is only available after a failover, which doesn't meet the requirement for 'immediately available for viewing by other users' across regions during normal operations or temporary outages.
Azure Blob Storage RA-GRS
Read-Access Geo-Redundant Storage (RA-GRS) replicates your data to a secondary region hundreds of miles away from the primary region. It provides read access to the data in the secondary region, allowing for high availability and disaster recovery, even if the primary region becomes unavailable.
- Geo-redundant: data replicated to a secondary region.
- Provides read access to data in the secondary region.
- Offers eventual consistency for reads from the secondary.
- Highest durability and availability for Blob Storage.
Memory trick: Redundancy: Local, Zonal, Geographic, Read-Access Geographic.