An insurance company is designing a disaster recovery (DR) solution to replicate its on-pr… — Microsoft Azure Solutions Architect (AZ-305)

An insurance company is designing a disaster recovery (DR) solution to replicate its on-premises VMware workloads to Azure. The workload consists of two virtual machines:

- VM-App: An application server with an average write churn of $3\text{ MB/s}$ and a peak write churn of $8\text{ MB/s}$ .
- VM-Data: A database server with a single data disk that experiences an average write churn of $28\text{ MB/s}$ and a peak write churn of $45\text{ MB/s}$ .

The DR solution must support a Recovery Point Objective (RPO) of under 2 hours and a Recovery Time Objective (RTO) of under 1 hour.

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

Replicate VM-App to Azure by using Azure Site Recovery.Answer
Configure SQL Server Always On Availability Groups to replicate the database from the on-premises environment to SQL Server on Azure Virtual Machines.Answer
C
Replicate VM-Data to Azure by using Azure Site Recovery.
D
Replicate VM-Data directly to a Read-Access Geo-Redundant Storage (RA-GRS) account to enable active-active database writes across regions.

Answer

Replicate VM-App to Azure by using Azure Site Recovery, and configure SQL Server Always On Availability Groups to replicate the database from the on-premises environment to SQL Server on Azure Virtual Machines.

The correct solution involves replicating the low-churn application VM (VM-App) using Azure Site Recovery, and using SQL Server Always On Availability Groups for the database VM (VM-Data). Since VM-Data's write churn (

28\text{ MB/s}

average,

45\text{ MB/s}

peak) exceeds the standard ASR limit of

20\text{ MB/s}

per Premium SSD disk, standard ASR replication is not suitable. Always On Availability Groups handle high-churn databases efficiently and can meet the strict RPO/RTO requirements.

Step-by-Step Solution

Analyze the write churn for VM-App and VM-Data.

VM-App has an average write churn of

3\text{ MB/s}

and a peak of

8\text{ MB/s}

. VM-Data has an average write churn of

28\text{ MB/s}

and a peak of

45\text{ MB/s}

This establishes whether the workloads fall within the standard write churn limits of Azure Site Recovery.

Compare write churn against Azure Site Recovery limits.

VM-App is well below the standard

20\text{ MB/s}

per Premium SSD disk limit. VM-Data exceeds the

20\text{ MB/s}

per Premium SSD disk limit.

This determines which virtual machines can be safely replicated using Azure Site Recovery.

Determine the appropriate replication method for the high-churn database workload.

Since VM-Data cannot use Azure Site Recovery due to churn limits, SQL Server Always On Availability Groups must be used to replicate the SQL Server database to Azure VMs.

This ensures the database replication remains healthy and meets the RPO and RTO requirements.

Key Concept

Azure Site Recovery limits require checking disk write churn against limits (typically

20\text{ MB/s}

per Premium SSD disk); workloads exceeding these limits must use native replication solutions like SQL Server Always On Availability Groups.

Question

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Step-by-Step Solution

Key Concept

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