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AZ-305 · Question #267

Drag and Drop Question You are designing a virtual machine that will run Microsoft SQL Server and contain two data disks. The first data disk will store log files, and the second data disk will…

The correct answer is Log: None; Data: ReadOnly. For SQL Server log disks, 'None' (no caching) is the correct choice because write-ahead logging requires that log writes be immediately committed to durable storage - enabling caching could risk data loss or corruption if the VM crashes before the cache is flushed. For SQL…

Submitted by helene.fr· Mar 6, 2026Design and Implement Storage Solutions for Azure Virtual Machines (Azure Solutions Architect / AZ-305 / AZ-104)

Question

Drag and Drop Question You are designing a virtual machine that will run Microsoft SQL Server and contain two data disks. The first data disk will store log files, and the second data disk will store data. Both disks are P40 managed disks. You need to recommend a host caching method for each disk. The method must provide the best overall performance for the virtual machine while preserving the integrity of the SQL data and logs. Which host caching method should you recommend for each disk? To answer, drag the appropriate methods to the correct disks. Each method may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content. NOTE: Each correct selection is worth one point. Answer:

Exhibit

AZ-305 question #267 exhibit

Answer Area

Drag items

NoneReadOnlyReadWrite

Correct arrangement

  • Log: None
  • Data: ReadOnly

Explanation

For SQL Server log disks, 'None' (no caching) is the correct choice because write-ahead logging requires that log writes be immediately committed to durable storage - enabling caching could risk data loss or corruption if the VM crashes before the cache is flushed. For SQL Server data disks, 'ReadOnly' caching is optimal because data files are frequently read (e.g., index lookups, query scans) and reads benefit significantly from the Azure host cache, while writes bypass the cache entirely (write-through behavior), preserving data integrity. This combination maximizes IOPS/throughput performance while ensuring SQL transactional consistency.

Topics

#Azure Managed Disks#Host Caching#SQL Server Performance#Azure VM Storage

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