You need to design a highly available Azure SQL database that meets the following requirements:
• Failover between replicas of the database must occur without any data loss.
• The database must remain available in the event of a zone outage.
• Costs must be minimized.
Which deployment option should you use?
To design a highly available Azure SQL database that meets the requirements of failover without data loss, resilience to zone outages, and cost minimization, Azure SQL Database Business Critical is the most suitable option. This tier provides high availability with automatic failover and zero data loss by maintaining multiple synchronized replicas. Furthermore, it supports zone-redundant configurations, which ensure that the database remains operational even during a zone outage, without additional cost penalties compared to other high availability options.
B. Azure SQL Database Business Critical Azure SQL Database Business Critical tier is designed to provide high availability with zero data loss during failover, which meets one of the main requirements of the scenario. Additionally, Azure SQL Database Business Critical tier offers zone redundant configurations, which means that replicas of the data are stored in different availability zones. This means the database will remain available in the event of a zone outage, meeting another requirement of the scenario. Azure SQL Managed Instance General Purpose, while providing automatic backups and high availability within a single region, doesn't support the required zone redundancy. Please note, while Business Critical tier might appear costly, the requirement is to minimize costs, not to choose the least costly option. Considering the high availability and zero data loss requirements, Business Critical tier would be the most cost-effective choice.
Azure SQL Managed Instance General Purpose, as it's cheaper than Azure SQL Database Business Critical By selecting a zone-redundant configuration, you can make your Business Critical or General Purpose instances resilient to a much larger set of failures, including catastrophic datacenter outages, without any changes to the application logic. You can also convert any existing Business Critical or General Purpose instances to zone-redundant configuration. https://learn.microsoft.com/en-us/azure/azure-sql/managed-instance/high-availability-sla?view=azuresql-mi&preserve-view=true
Zone-redundancy is currently in public preview for the General Purpose service tier (2024-07) - so you are right, but I don't think the exams rely on public previews, only on public available features: https://learn.microsoft.com/en-us/azure/azure-sql/managed-instance/instance-zone-redundancy-configure
B is the answer. https://learn.microsoft.com/en-us/azure/azure-sql/database/sql-database-paas-overview?view=azuresql#service-tiers The Business Critical service tier is designed for OLTP applications with high transaction rates and low latency I/O requirements. It offers the highest resilience to failures by using several isolated replicas.
https://learn.microsoft.com/en-us/azure/azure-sql/database/high-availability-sla?view=azuresql&tabs=azure-powershell#premium-and-business-critical-service-tier-zone-redundant-availability By default, the cluster of nodes for the premium availability model is created in the same datacenter. With the introduction of Azure Availability Zones, SQL Database can place different replicas of the Business Critical database to different availability zones in the same region. To eliminate a single point of failure, the control ring is also duplicated across multiple zones as three gateway rings (GW). The routing to a specific gateway ring is controlled by Azure Traffic Manager (ATM). Because the zone-redundant configuration in the Premium or Business Critical service tiers doesn't create additional database redundancy, you can enable it at no extra cost. By selecting a zone-redundant configuration, you can make your Premium or Business Critical databases resilient to a much larger set of failures, including catastrophic datacenter outages, without any changes to the application logic.
D. Azure SQL Managed Instance General Purpose
It is a repeated question, the answer is B. Azure SQL Database Business Critical
Azure SQL Database Business Critical
Minimize costs
Azure SQL DB Standard tier only supports LRS. https://learn.microsoft.com/en-us/azure/azure-sql/database/high-availability-sla?view=azuresql&tabs=azure-powershell#basic-standard-and-general-purpose-service-tier-locally-redundant-availability