AZ-204 Develop for Azure storage Practice Test 3 — 15 Questions

Question 1

You design an application that writes millions of small sensor readings (each ~100 bytes) to Azure Blob Storage. The data is appended to files every minute and after 7 days it is archived for compliance. You need to minimize write costs and storage costs. Which blob type and tier strategy should you use?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Append blobs with Hot tier and a lifecycle rule to move to Archive after 7 days.. Append blobs are optimized for append operations, making them ideal for continuously adding small sensor readings without rewriting existing data, which minimizes write costs. Moving the blobs to the Archive tier after 7 days via a lifecycle rule reduces storage costs for compliance data, as Archive is the lowest-cost tier for infrequently accessed data.

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Block blobs with Hot tier and a lifecycle rule to move to Cool after 7 days.

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Page blobs with Premium tier.

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Append blobs with Cool tier and no lifecycle rule.

Question 2

You need to store terabytes of archival data that must be retained for 10 years. The data is accessed once or twice per year. You need to minimize storage costs. Which Azure Storage tier should you use?

Accepted Answer

Archive. The Archive tier is designed for data that is rarely accessed (a few times per year or less) and has a flexible retrieval latency of several hours, making it ideal for long-term retention of terabytes of archival data for 10 years at the lowest storage cost. It offers the lowest per-GB storage price among Azure Blob Storage tiers, directly meeting the requirement to minimize costs for infrequently accessed data.

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Cool

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Hot

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Premium

Question 3

You are designing a solution that writes millions of small log records (each 200 bytes) to Azure Blob Storage. The logs are written every second, always appended to a single file. The file must be read periodically by a batch process that reads the entire file. You need to maximize write throughput and minimize storage costs. Which blob type and access strategy should you choose?

Accepted Answer

Use Append blobs and write each log entry as an append block. Append blobs are optimized for append operations, making them ideal for writing millions of small log records sequentially to a single file. Data is written in append blocks. For millions of small log entries, these entries would typically be buffered and written together as larger append blocks (up to 4 MB each) to optimize performance and and stay within the append blob's 50,000 block limit. This provides high throughput for append-heavy workloads and minimizes storage costs by storing data in a single blob.

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Use Block blobs and append the data to a single blob

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Use Page blobs and write each log entry to a page

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Use Block blobs and create a new blob for each log entry

Question 4

You need to store large files that are written once and then frequently read for the first 30 days. After 30 days, the files are rarely accessed (once or twice per year) but must remain available for 5 years. You want to minimize storage costs. Which storage tier and lifecycle management rule should you apply?

Accepted Answer

Hot tier with a lifecycle rule to move to Cool after 30 days. The Hot tier is optimized for frequent reads, and the lifecycle rule moves data to the Cool tier after 30 days when access drops, balancing performance and cost. After 30 days, the files are rarely accessed, so moving them to Cool (not Archive) keeps them available for occasional reads without the high retrieval costs and latency of Archive. This minimizes storage costs while meeting the 5-year retention requirement.

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Cool tier with a lifecycle rule to move to Archive after 30 days

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Hot tier with a lifecycle rule to move to Archive after 30 days

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Archive tier with a lifecycle rule to move to Cool after 30 days

Question 5

You need to store billions of small log entries (each ~200 bytes) written in chronological order from multiple producers. The logs are read sequentially in bulk once per day. You need to maximize write throughput and minimize storage costs. Which Azure Storage solution should you choose?

Accepted Answer

Append Blob in Blob Storage. Append Blob in Blob Storage is optimized for append operations, making it ideal for writing small log entries in chronological order from multiple producers. It provides high write throughput because each append operation is atomic and can be performed concurrently, and it minimizes storage costs by storing data in a cost-effective blob tier without the overhead of indexing or metadata management required by other solutions.

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Block Blob in Blob Storage with high block count

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Azure Data Lake Storage Gen2 with hierarchical namespace

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Azure Files with SMB protocol

Question 6

You need to store millions of small JSON documents (each ~1 KB) that are frequently updated by multiple concurrent users. You require low-latency access to individual documents. Which Azure Storage solution should you use?

Accepted Answer

Azure Table Storage. Azure Table Storage is a NoSQL key-value store optimized for storing large volumes of structured, non-relational data with low-latency access by partition key and row key. It supports millions of small JSON documents (~1 KB) and handles frequent concurrent updates via optimistic concurrency control using ETags, making it ideal for this scenario.

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Azure Blob Storage with Block blobs

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Azure Files with SMB protocol

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Azure Cosmos DB for NoSQL

Question 7

You are designing a backup solution for a virtual machine. Monthly backups are large VHD files (up to 1 TB) that must be retained for 7 years. After creation, backups are accessed only rarely (once or twice per year). You need to minimize storage cost. Which storage tier should you use for the VHD files?

Accepted Answer

Archive tier. The Archive tier is the correct choice because it offers the lowest storage cost for data that is rarely accessed (once or twice per year) and has a long retention period (7 years). Azure Archive storage is optimized for data that can tolerate a retrieval latency of several hours, which is acceptable given the infrequent access pattern of these monthly backup VHD files.

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Hot tier

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Cool tier

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Premium tier

Question 8

You are building a serverless application that needs to store user profile data. The data includes simple fields like name, email, and preferences. The data is frequently accessed by user ID. You need a schema-less, low-latency storage solution that is cost-effective for millions of small records. Which Azure Storage solution should you use?

Accepted Answer

Azure Table Storage. Azure Table Storage is a NoSQL key-value store that is schema-less, making it ideal for storing user profile data with varying fields like name, email, and preferences. It offers low-latency access by user ID via the PartitionKey and RowKey, and it is cost-effective for millions of small records because you pay only for the storage consumed, with no minimum charge per record.

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Azure Blob Storage

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Azure Queue Storage

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Azure File Storage

Question 9

You are designing a solution to ingest billions of small IoT sensor messages (each ~500 bytes). Messages arrive at high velocity and must be retained for 90 days. You need to query the data efficiently by device ID and timestamp. You want to minimize storage cost and write latency. Which Azure Storage solution should you use?

Accepted Answer

Azure Table Storage. Azure Table Storage is ideal for this scenario because it provides a cost-effective, schema-less NoSQL store that supports high-volume ingestion of billions of small messages with low write latency. Its partition key (device ID) and row key (timestamp) design enables efficient point queries by device and time range, while the 90-day retention aligns with Table Storage's lifecycle management capabilities.

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Azure Blob Storage with JSON logs

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Azure Queue Storage

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Azure File Storage

Question 10

You need to store large amounts of unstructured data (images and videos) that are accessed rarely (a few times per year) but must be available within minutes when requested. The data must be geo-redundant for disaster recovery. You want to minimize storage costs. Which storage tier and redundancy option should you choose?

Accepted Answer

Cool storage tier with geo-redundant storage (GRS). The Cool storage tier is designed for data that is infrequently accessed (a few times per year) and stored for at least 30 days, offering lower storage costs than Hot tier while still providing low-latency retrieval within minutes. Geo-redundant storage (GRS) replicates data to a paired secondary region, ensuring disaster recovery with geo-redundancy. This combination meets the requirements of rare access, minutes-availability, geo-redundancy, and minimal cost.

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Hot storage tier with geo-redundant storage (GRS)

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Archive storage tier with read-access geo-redundant storage (RA-GRS)

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Premium storage tier with local redundant storage (LRS)

Question 11

You need to store billions of small log entries (each ~200 bytes) generated from multiple IoT devices. The logs are written in chronological order and are rarely updated. You need to run queries that scan large ranges of data by timestamp each day. You want to maximize write throughput and minimize storage costs. Which Azure Storage solution should you choose?

Accepted Answer

Azure Table Storage with a partition key combining device ID and date, and row key as timestamp.. Azure Table Storage is ideal for this scenario because it supports high-volume, low-cost storage of structured log data with efficient range queries. By using a partition key of device ID combined with date, you distribute writes across partitions for high throughput, while the row key as timestamp enables fast, server-side range scans over chronological data without the overhead of a separate index.

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Azure Cosmos DB SQL API with a collection partitioned by timestamp.

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Azure Blob Storage with append blobs and a custom index for timestamp queries.

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Azure SQL Database with a clustered columnstore index.

Question 12

Your company stores backup files in an Azure Blob Storage account. These files are written once and then need to be retained for 7 years. During the first year, the files are accessed weekly. After the first year, they are accessed rarely (once per month). You want to minimize storage costs. Which combination of access tiers and lifecycle management should you apply?

Accepted Answer

Store in Hot tier and move to Cool after 1 year, then to Archive after 7 years.. For data accessed weekly during the first year, the Hot tier is appropriate, or the Cool tier if storage cost savings significantly outweigh transaction costs. For data accessed monthly after the first year, the Cool tier is the most cost-effective choice, balancing lower storage costs with reasonable access costs without incurring rehydration fees or significant latency. The Archive tier is suitable only for data that is rarely accessed (e.g., less than once a year) and can tolerate significant retrieval latency and cost. Therefore, the optimal strategy among the given options is to store in Hot for the first year, move to Cool for the subsequent years of monthly access, and then to Archive only after the 7-year retention period if access truly ceases.

Answer

Store in Cool tier and move to Archive after 1 year.

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Store directly in Archive tier and rehydrate to Cool when needed for access.

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Store in Hot tier and move to Archive after 90 days.

Question 13

You need to store billions of small telemetry data entries (each ~100 bytes) from IoT devices. The data is written once and rarely updated. You need to run analytical queries on the last 30 days of data daily. The queries scan large ranges of data by timestamp and require sub-second response times. You need the lowest storage cost while meeting query latency requirements. Which Azure Storage solution should you use?

Accepted Answer

Azure Blob Storage with hot access tier and Data Lake Storage Gen2.. Azure Blob Storage with the hot access tier is suitable for data that is accessed frequently (daily queries on the last 30 days), providing lower transaction costs compared to the cool tier for active data. Azure Data Lake Storage Gen2, built on Blob Storage, enables hierarchical namespace and POSIX-like access, allowing efficient analytical queries on large timestamp-ranged data with sub-second response times via partitioning and parallel processing, meeting the performance and scalability requirements at a cost-effective price point for the storage of billions of small entries.

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Azure Table Storage with a timestamp partition key.

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Azure Cosmos DB with SQL API and automatic indexing.

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Azure Blob Storage with cool access tier and Azure Data Lake Storage Gen2.

Question 14

You are building a web application that allows users to upload profile pictures. The images are up to 5 MB in size and must be stored durably. The images are accessed infrequently after upload (a few times per month). You want to minimize storage costs while ensuring the data is available within seconds when requested. Which Azure Blob Storage access tier should you use for the blob container?

Accepted Answer

Cool. The Cool tier is the optimal choice because the images are accessed infrequently (a few times per month) and are up to 5 MB in size. Cool tier offers lower storage cost than Hot tier while still providing sub-second latency for data retrieval, meeting the requirement of availability within seconds. Archive tier would have the lowest storage cost but incurs a multi-hour rehydration delay, violating the seconds-level availability requirement.

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Hot

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