Exam AZ-900 topic 1 question 2 discussion

Answer is correct. Geo-redundant storage (with GRS or GZRS) replicates your data to another physical location in the secondary region to protect against regional outages. However, that data is available to be read only if the customer or Microsoft initiates a failover from the primary to secondary region. When you enable read access to the secondary region, your data is available to be read at all times, including in a situation where the primary region becomes unavailable. For read access to the secondary region, enable read-access geo-redundant storage (RA-GRS) or read-access geo-zone-redundant storage (RA-GZRS).

I think it 's a mistake, it should be "B. Read-access geo-redundant storage" instead of "B. Read-only geo-redundant storage"

Requirement 1: "Data must be stored on multiple nodes." This implies data replication for fault tolerance. ✅ All Azure redundancy options replicate data to multiple nodes. 📌 Requirement 2: "Data must be stored on nodes in separate geographic locations." This requires geo-replication—data must be copied to another region, such as Los Angeles ⇄ New York. ✅ Only Geo-redundant Storage (GRS) and Read-access Geo-redundant Storage (RA-GRS) satisfy this. ❌ Locally Redundant Storage (LRS) and Zone-Redundant Storage (ZRS) do not replicate across regions. 📌 Requirement 3: "Data can be read from the secondary location as well as from the primary location." This is read-access from the secondary location, which is only provided by RA-GRS. ✅ RA-GRS: You can read data from the secondary region. ❌ GRS: Secondary region is not readable, only used during failover.

Azure Read-Access Geo-Redundant Storage (RA-GRS) provides a higher level of data durability and availability than standard Geo-Redundant Storage (GRS) by enabling read-only access to data in the secondary region, even when the primary region is operational or during an outage. This configuration ensures your data is replicated to a primary region and then asynchronously to a geographically distant secondary region, allowing for read operations from the secondary endpoint during primary region disruptions, and increasing the SLA for read operations to 99.99%.

Read-only geo-redundant storage (RA-GRS) is the only option that satisfies all the requirements, including read access to the secondary location across geographic regions.

For more context check https://learn.microsoft.com/en-us/azure/storage/common/storage-redundancy#read-access-to-data-in-the-secondary-region The correct answer should be Read-access geo-redundant storage and option B should be changed from "Read-only geo-redundant storage" to "Read-access geo-redundant storage"

Correct terminology is read-access geo-redundant storage (RA-GRS)

it's not Read-only it should be Read acces

B. Read-only geo-redundant storage

O armazenamento com redundância geográfica (com GRS ou GZRS) replica seus dados para outro local físico na região secundária para proteger contra interrupções regionais. No entanto, esses dados estarão disponíveis para leitura somente se o cliente ou a Microsoft iniciar um failover da região primária para a secundária.

B. Read-only geo-redundant storage

B. Read-only geo-redundant storage

Key Tips: RA-GRS = Read access to secondary (for geo-failover or read scaling). GRS = No read access (only disaster recovery).

https://learn.microsoft.com/en-us/azure/storage/common/storage-redundancy

Read-Access Geo-Redundant Storage allows read access to the secondary location, in Geo-Redundant Storage there is no read access until failure

A does not allow to ready secondary region unless there is failure from first one. But question did not mention that restriction. "As well As first region", so it should be B

B is correct: Read Access Geo Zone Reduant Storage - 3x copies of data in seperate availability zones data centre - 3x copies in a secondary region (but one location) - Read access in secondary region even if primary region is functional - Read access in secondary region if primary region is down