Microsoft Azure Architect Design (AZ-304) Practice Test

The choice that ensures virtual machines remain available during disk migration from an on-premises Hyper-V cluster to Azure involves using Azure Site Recovery. This service is designed to provide high availability and business continuity through replication and failover capabilities, allowing for the migration of VMs without downtime. Azure Site Recovery enables you to replicate and recover VMs seamlessly while they are still running. It orchestrates the entire migration process and ensures that the VM remains operational even as the disk migration takes place. This is crucial for businesses that cannot afford downtime or service interruptions during such transitions. In contrast, simply implementing an Azure Storage account and using AzCopy does not guarantee VM availability during migration. AzCopy is a tool for copying data and files to and from Azure storage, but does not provide the necessary orchestration or failover features required for live VM migrations, which is what makes Azure Site Recovery the superior choice. Implementing disk snapshots alone could provide a way to backup data, but it does not facilitate the active migration of VMs or provide the required continuity during the transfer process. Similarly, using the Data Migration Assistant is primarily designed for assessing and migrating databases and would not cater effectively to the ongoing availability of virtual machines during their migration.