Blob storage (block, append, page) in Azure - Mini Project: Build & Apply

Azure Blob Storage: Block, Append, and Page Blobs

📖 Scenario: You are working for a company that needs to store different types of files in Azure Blob Storage. Some files are large and uploaded in parts, some are logs that need to be appended continuously, and some are files that require random read/write access.You will create an Azure Storage container and configure three types of blobs: block blob, append blob, and page blob to handle these different needs.

🎯 Goal: Build an Azure Storage container with three blobs: a block blob for large file uploads, an append blob for log data, and a page blob for random read/write operations.

📋 What You'll Learn

Create an Azure Storage container named projectcontainer.

Create a block blob named largefile.txt inside the container.

Create an append blob named logfile.txt inside the container.

Create a page blob named pagedata.vhd with size 5120 bytes inside the container.

💡 Why This Matters

🌍 Real World

Many applications need to store files differently: large files in parts, logs that grow over time, or files needing random access. Azure Blob Storage offers block, append, and page blobs to meet these needs.

💼 Career

Cloud engineers and developers often configure blob storage types to optimize storage costs and performance for different data types.

1

Create the Azure Storage container

Write the Azure CLI command to create a storage container named projectcontainer in the storage account mystorageaccount.

Azure

# Your Azure CLI command here to create the container

Hint

Use az storage container create with --name and --account-name options.

2

Create the block blob and append blob

Write two Azure CLI commands: one to upload a block blob named largefile.txt from local file largefile.txt, and another to create an empty append blob named logfile.txt inside the container projectcontainer in storage account mystorageaccount.

Azure

az storage container create --name projectcontainer --account-name mystorageaccount
# Upload block blob largefile.txt
# Create empty append blob logfile.txt

Hint

Use az storage blob upload for block blob upload and az storage blob create --type AppendBlob to create an empty append blob.

3

Create the page blob

Write the Azure CLI command to create a page blob named pagedata.vhd with size 5120 bytes inside the container projectcontainer in storage account mystorageaccount.

Azure

az storage container create --name projectcontainer --account-name mystorageaccount
az storage blob upload --container-name projectcontainer --file largefile.txt --name largefile.txt --account-name mystorageaccount
az storage blob create --container-name projectcontainer --name logfile.txt --type AppendBlob --account-name mystorageaccount
# Create page blob pagedata.vhd with size 5120 bytes

Hint

Use az storage blob create --type PageBlob --size 5120 to create the page blob.

4

Verify the blobs in the container

Write the Azure CLI command to list all blobs inside the container projectcontainer in storage account mystorageaccount to verify the block, append, and page blobs are created.

Azure

az storage container create --name projectcontainer --account-name mystorageaccount
az storage blob upload --container-name projectcontainer --file largefile.txt --name largefile.txt --account-name mystorageaccount
az storage blob create --container-name projectcontainer --name logfile.txt --type AppendBlob --account-name mystorageaccount
az storage blob create --container-name projectcontainer --name pagedata.vhd --type PageBlob --size 5120 --account-name mystorageaccount
# List blobs in projectcontainer

Hint

Use az storage blob list with --container-name and --account-name to list blobs.

Practice

1. Which type of Azure Blob storage is best suited for storing large files that are uploaded in blocks and can be updated by replacing blocks?

easy

A. Append blob

B. Page blob

C. Block blob

D. File blob

Solution

1. Step 1: Understand block blob usage

   Block blobs are designed to store large files uploaded in blocks and allow updating by replacing blocks.

2. Step 2: Compare with other blob types

   Append blobs are for append-only operations, and page blobs are optimized for random read/write operations, not block uploads.

3. Final Answer:

   Block blob -> Option C

4. Quick Check:

   Block blob = large files in blocks [OK]

Hint: Block blobs store large files in blocks, perfect for uploads [OK]

Common Mistakes:

• Confusing append blob with block blob
• Thinking page blob is for block uploads
• Selecting non-existent blob types

2. Which of the following is the correct way to create an append blob using Azure CLI?

easy

A. az storage blob create --container-name mycontainer --name myappendblob --type AppendBlob

B. az storage blob create --container-name mycontainer --name myappendblob --type BlockBlob

C. az storage blob create --container-name mycontainer --name myappendblob --type PageBlob

D. az storage blob create --container-name mycontainer --name myappendblob --type FileBlob

Solution

1. Step 1: Identify correct blob type syntax

   The Azure CLI uses --type AppendBlob to create an append blob.

2. Step 2: Verify other options

   BlockBlob and PageBlob are valid types but not for append blobs; FileBlob is invalid.

3. Final Answer:

   az storage blob create --container-name mycontainer --name myappendblob --type AppendBlob -> Option A

4. Quick Check:

   Append blob creation uses --type AppendBlob [OK]

Hint: Use --type AppendBlob to create append blobs in Azure CLI [OK]

Common Mistakes:

• Using BlockBlob type for append blobs
• Using PageBlob type for append blobs
• Using invalid blob type names

3. Consider this code snippet using Azure SDK to upload data to a blob:

blob_client = container_client.get_blob_client('myblob')
blob_client.upload_blob(data, blob_type='PageBlob')

What will happen if the data size is not a multiple of 512 bytes?

medium

A. Upload will fail with an error about data size alignment

B. Upload will succeed with data padded to 512-byte boundaries

C. Upload will succeed but truncate extra bytes

D. Upload will convert data to block blob automatically

Solution

1. Step 1: Understand page blob requirements

   Page blobs require data size to be a multiple of 512 bytes for alignment.

2. Step 2: Analyze upload behavior

   If data size is not aligned, the upload will fail with an error about size alignment.

3. Final Answer:

   Upload will fail with an error about data size alignment -> Option A

4. Quick Check:

   Page blob data size must be multiple of 512 bytes [OK]

Hint: Page blobs need 512-byte aligned data size [OK]

Common Mistakes:

• Assuming automatic padding of data
• Thinking upload truncates data silently
• Believing blob type auto-conversion occurs

4. You have an append blob but your application tries to overwrite existing data instead of appending. What is the likely cause and fix?

medium

A. Using page blob API calls on append blob

B. Using append_block method instead of upload_blob

C. Creating the blob as a block blob instead of append blob

D. Using upload_blob with overwrite=True instead of append_block method

Solution

1. Step 1: Identify append blob usage

   Append blobs require using append_block to add data without overwriting.

2. Step 2: Analyze the overwrite behavior

   Using upload_blob with overwrite=True replaces existing data, not appends.

3. Final Answer:

   Using upload_blob with overwrite=True instead of append_block method -> Option D

4. Quick Check:

   Append blobs append with append_block, not upload_blob overwrite [OK]

Hint: Use append_block to add data, not upload_blob overwrite [OK]

Common Mistakes:

• Confusing append_block and upload_blob methods
• Creating wrong blob type
• Using page blob APIs on append blobs

5. You need to design a system that stores virtual machine disks requiring frequent random read/write operations with low latency. Which Azure blob type should you choose and why?

hard

A. Append blob, because it allows efficient appending of logs

B. Page blob, because it supports random read/write with 512-byte pages

C. Block blob, because it supports large file uploads in blocks

D. File blob, because it supports file system semantics

Solution

1. Step 1: Identify requirements for VM disks

   VM disks need frequent random read/write with low latency and page-level updates.

2. Step 2: Match blob type to requirements

   Page blobs support random read/write operations in 512-byte pages, ideal for VM disks.

3. Step 3: Exclude other blob types

   Block blobs are for large uploads, append blobs for append-only logs, and file blob is not a valid Azure blob type.

4. Final Answer:

   Page blob, because it supports random read/write with 512-byte pages -> Option B

5. Quick Check:

   VM disks use page blobs for random read/write [OK]

Hint: Page blobs support random read/write, perfect for VM disks [OK]

Common Mistakes:

• Choosing block blob for VM disks
• Confusing append blob with page blob
• Selecting non-existent file blob type