An organization has a financial analysis application deployed in the East Asia region. The… — Microsoft Azure Solutions Architect (AZ-305)

An organization has a financial analysis application deployed in the East Asia region. The application consists of two Azure virtual machines: `AppWeb-VM01` (web tier) and `AppDB-VM01` (database tier running SQL Server).

You are designing a disaster recovery (DR) solution to the Southeast Asia region. The solution must meet the following requirements:
* The database tier must have a recovery point objective (RPO) of $10\text{ minutes}$ and a recovery time objective (RTO) of $1\text{ hour}$ .
* The web tier must have an RPO of $4\text{ hours}$ and an RTO of $2\text{ hours}$ .

During peak hours, the disk write churn rates are as follows:
* `AppWeb-VM01`: $1.5\text{ MB/s}$ total.
* `AppDB-VM01` OS disk: $1.8\text{ MB/s}$ .
* `AppDB-VM01` SQL Server data disk (Premium SSD v1): $27\text{ MB/s}$ .
* `AppDB-VM01` SQL Server TempDB disk (Premium SSD v1): $12\text{ MB/s}$ .

Which two actions should you include in the disaster recovery design?

Replicate AppWeb-VM01 to the target region by using Azure Site Recovery.Answer
Replicate the database tier by using SQL Server Always On Availability Groups to the target region.Answer
C
Replicate AppDB-VM01 to the target region by using Azure Site Recovery with the high-churn limits option enabled.
D
Configure Azure Backup with cross-region restore (CRR) for the daily backup points of AppDB-VM01.

Answer

Replicate AppWeb-VM01 to the target region by using Azure Site Recovery, and replicate the database tier by using SQL Server Always On Availability Groups to the target region.

Replicating the web tier virtual machine with Azure Site Recovery is correct because its total write churn of

1.5\text{ MB/s}

is well within ASR limits. Replicating the database tier with SQL Server Always On Availability Groups is correct because the database data disk write churn of

27\text{ MB/s}

exceeds the

20\text{ MB/s}

threshold supported by Azure Site Recovery for Premium SSD v1 disks, requiring an application-level replication strategy to maintain the 10-minute RPO.

Step-by-Step Solution

Analyze Azure Site Recovery limits for Premium SSD v1.

The standard disk-level write churn limit for Azure Site Recovery is

10\text{ MB/s}

per disk, which can be configured up to

20\text{ MB/s}

per disk when the high-churn option is enabled.

This establishes the boundaries of what workloads can be protected using host-based replication with Azure Site Recovery.

Compare the virtual machines' disk write churn rates against the limits.

AppWeb-VM01 (

1.5\text{ MB/s}

) and the AppDB-VM01 OS disk (

1.8\text{ MB/s}

) are well below the limits. However, the database data disk write churn (

27\text{ MB/s}

) exceeds the absolute limit of

20\text{ MB/s}

This identifies which virtual machines can be replicated using Azure Site Recovery and which cannot.

Select the appropriate disaster recovery strategy for the database tier.

Design native database replication using SQL Server Always On Availability Groups to replicate database transactions to a secondary server running in the target region.

Since Azure Site Recovery cannot replicate the high-churn data disk, native replication is required to achieve the 10-minute RPO.

Key Concept

Azure Site Recovery has strict write churn limits (

10\text{ MB/s}

standard,

20\text{ MB/s}

high-churn per Premium SSD v1 disk). Workloads exceeding these limits must be replicated using application-native replication solutions such as SQL Server Always On Availability Groups.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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