A global content delivery network (CDN) uses Azure Blob Storage to host static website content and large media files. To ensure high availability and disaster recovery, the storage account is configured for Geo-Redundant Storage (GRS). However, the CDN requires read access to the secondary region even if the primary region is unavailable, without a full failover. Which additional configuration should be applied to the GRS storage account?
- AImplement client-side caching with Azure Cache for Redis
- BConfigure Zone-Redundant Storage (ZRS)
- CSwitch to Locally-Redundant Storage (LRS) with a manual failover plan
- DEnable read-access geo-redundant storage (RA-GRS)
Show answer & explanationAnswer & explanation
Correct answer: D. Enable read-access geo-redundant storage (RA-GRS)
Read-access geo-redundant storage (RA-GRS) builds upon GRS by providing read access to the secondary replica. This allows applications to read data from the secondary region if the primary becomes unavailable, without requiring a full storage account failover, which is ideal for CDNs needing high availability.
Why the other options are wrong
- A. Client-side caching can improve performance but doesn't inherently provide read access to a geo-replicated secondary region.
- B. ZRS provides synchronous replication across availability zones within a single region, not cross-region disaster recovery.
- C. LRS only provides local redundancy within a single data center and does not offer cross-region disaster recovery or read access to a secondary.
Azure Blob Storage RA-GRS
Read-access geo-redundant storage (RA-GRS) provides read-only access to data in the secondary region in addition to geo-replication. This allows applications to read from the secondary endpoint during a primary region outage, offering higher availability and disaster recovery capabilities.
- Replicates data to a secondary region (as GRS).
- Provides read-only access to data in the secondary region.
- Enables high availability during primary region outages.
- No need for storage account failover for reads.
- Higher cost than GRS but offers better read availability.
Memory trick: LRS, ZRS, GRS, RA-GRS: The more letters, the more copies and resilience.