A global maritime logistics enterprise is designing a disaster recovery (DR) solution to r… — Microsoft Azure Solutions Architect (AZ-305)

A global maritime logistics enterprise is designing a disaster recovery (DR) solution to replicate workloads from Azure North Europe to West Europe. The tracking architecture consists of two main virtual machines:

- `vm-track1`: Hosts the cargo tracking API and contains a Standard SSD OS disk with a write churn of $1\text{ MB/s}$ and a Premium SSD data disk with a write churn of $8\text{ MB/s}$ (total VM churn of $9\text{ MB/s}$ ).
- `vm-db1`: Hosts a high-transaction PostgreSQL database and contains a Premium SSD OS disk with a write churn of $2\text{ MB/s}$ and two Premium SSD data disks: Data Disk 1 with a write churn of $15\text{ MB/s}$ and Data Disk 2 with a write churn of $22\text{ MB/s}$ (total VM churn of $39\text{ MB/s}$ ).

The DR solution must guarantee a Recovery Point Objective (RPO) of $10\text{ minutes}$ and a Recovery Time Objective (RTO) of $1\text{ hour}$ for both workloads.

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

Replicate vm-track1 to the target region using Azure Site Recovery.Answer
B
Replicate vm-db1 to the target region using Azure Site Recovery with the high-churn replication policy.
Implement native PostgreSQL streaming replication from vm-db1 to a standby instance in the target region.Answer
D
Configure Azure Backup cross-region restore for both vm-track1 and vm-db1.

Answer

Replicate vm-track1 to the target region using Azure Site Recovery, and implement native PostgreSQL streaming replication from vm-db1 to a standby instance in the target region.

The correct design uses Azure Site Recovery to replicate vm-track1 because its write churn (

8\text{ MB/s}

on the data disk) is below the

10\text{ MB/s}

standard disk replication limit. For vm-db1, because Data Disk 2 experiences a write churn of

22\text{ MB/s}

(which exceeds the maximum ASR high-churn support limit of

20\text{ MB/s}

per disk), Azure Site Recovery cannot be used. Instead, native PostgreSQL streaming replication must be implemented to replicate the database to the target region while meeting the

10\text{ minutes}

RPO requirement.

Step-by-Step Solution

Analyze the write churn metrics for vm-track1.

The Standard SSD OS disk has a write churn of

1\text{ MB/s}

, and the Premium SSD data disk has a write churn of

8\text{ MB/s}

, with a total VM churn of

9\text{ MB/s}

To determine if Azure Site Recovery (ASR) can support replication, as the standard limits are

10\text{ MB/s}

per disk and

40\text{ MB/s}

per VM, which vm-track1 satisfies.

Analyze the write churn metrics for vm-db1.

The Premium SSD OS disk has a write churn of

2\text{ MB/s}

, Data Disk 1 has

15\text{ MB/s}

, and Data Disk 2 has

22\text{ MB/s}

, with a total VM churn of

39\text{ MB/s}

To verify if ASR can support replication. While the total VM churn (

39\text{ MB/s}

) is within the high-churn VM support limits, Data Disk 2's churn (

22\text{ MB/s}

) exceeds the maximum ASR high-churn limit of

20\text{ MB/s}

per disk.

Select the replication mechanism for both virtual machines based on churn and RPO/RTO requirements.

Replicate vm-track1 via ASR. For vm-db1, since ASR cannot support the disk churn, native database-level replication (such as PostgreSQL streaming replication) must be used to meet the

10\text{ minutes}

RPO.

Azure Backup cross-region restore is unsuitable as its replication and restore times cannot guarantee a

10\text{ minutes}

RPO and

1\text{ hour}

RTO.

Key Concept

Azure Site Recovery limits and native database replication for high write churn workloads.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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