A logistics company runs a fleet tracking application in the West US 2 region. The applica… — Microsoft Azure Solutions Architect (AZ-305)

A logistics company runs a fleet tracking application in the West US 2 region. The application's architecture includes two front-end web server virtual machines named Web-01 and Web-02, and a backend SQL Server database hosted on a single virtual machine named DB-01.

Web-01 and Web-02 both run on Standard SSD disks, each experiencing a continuous write churn of $1.5\text{ MB/s}$ . DB-01 uses three Premium SSD v1 disks:
* OS Disk: $2\text{ MB/s}$ average write churn
* Data Disk: $12\text{ MB/s}$ average write churn
* Transaction Log Disk: $56\text{ MB/s}$ average write churn

You are designing a disaster recovery (DR) solution to the East US region. The solution must meet the following requirements:
* The web servers must have a Recovery Point Objective (RPO) of 1 hour and a Recovery Time Objective (RTO) of 2 hours.
* The database must have an RPO of less than 10 seconds and an RTO of 15 minutes.

Which disaster recovery design should you recommend?

A
Configure Azure Site Recovery to replicate Web-01, Web-02, and DB-01 to the target region, enabling the High Churn replication policy on DB-01's virtual machine configuration.
B
Configure Azure Site Recovery to replicate Web-01 and Web-02, and configure an Azure SQL Auto-Failover Group to automate database replication for the SQL Server instance on DB-01.
Configure Azure Site Recovery to replicate Web-01 and Web-02 to the target region, and deploy SQL Server Always On Availability Groups to replicate the database to a target virtual machine in East US.Cevap
D
Configure Azure Site Recovery to replicate Web-01 and Web-02, and configure DB-01's disks on Read-Access Geo-Redundant Storage (RA-GRS) to allow database write workloads to resume in the secondary region during failover.

Cevap

Configure Azure Site Recovery to replicate the web servers (Web-01 and Web-02) to the target region, and deploy SQL Server Always On Availability Groups to replicate the database (DB-01) to a target virtual machine in the target region.

The correct design uses Azure Site Recovery to replicate the web tier virtual machines, while using SQL Server Always On Availability Groups to replicate the database tier. This is necessary because Azure Site Recovery has an absolute write churn limit of

54\text{ MB/s}

per Premium SSD v1 disk (even with High Churn enabled). DB-01's transaction log disk has a churn of

56\text{ MB/s}

, which exceeds this limit and would fail replication. Furthermore, block-level replication through Azure Site Recovery cannot guarantee the sub-10 second RPO required for the database tier, whereas native SQL Server Always On Availability Groups can.

Adım Adım Çözüm

Analyze the web tier disaster recovery requirements and capabilities.

Web-01 and Web-02 have an RPO of 1 hour and RTO of 2 hours, with

1.5\text{ MB/s}

churn. This is well within standard Azure Site Recovery (ASR) limits (up to

8\text{ MB/s}

for Standard SSD, and typical RPO is minutes, RTO is under 2 hours). Thus, ASR is suitable for the web tier.

To ensure the web tier can fail over within the given RTO/RPO limits using block-level VM replication.

Evaluate the database tier VM disk write churn against Azure Site Recovery limits.

DB-01 has a transaction log disk experiencing

56\text{ MB/s}

write churn. Azure Site Recovery's maximum support limit for a Premium SSD v1 disk is

20\text{ MB/s}

(Standard replication) and

54\text{ MB/s}

(High Churn replication). Since

56\text{ MB/s} > 54\text{ MB/s}

, DB-01 cannot be replicated using ASR.

To determine if ASR can support the write-intensive log disk of the database VM.

Select the correct database replication method to meet the near-zero RPO and RTO requirements.

A sub-10 second RPO requires native database-level replication. Deploying SQL Server Always On Availability Groups to a target database VM in the destination region ensures database transactions are replicated asynchronously or synchronously with near-zero RPO, completely bypassing ASR's disk churn limitations.

To select a replication technology that satisfies the database's specific RPO/RTO goals and bypasses hypervisor-level storage limits.

Anahtar Kavram

Azure Site Recovery limits and hybrid database replication design patterns

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Konular

Bu konudan daha fazla soru