Why Storage tiers (Hot, Cool, Archive) in Azure? - Purpose & Use Cases

The Big Idea

What if your data could organize itself to save you money and time without you lifting a finger?

The Scenario

Imagine you have a huge photo album stored on your computer. Some photos you look at every day, some only once in a while, and some you just want to keep safe but never really see. You try to keep all these photos in the same folder, using the same space and speed for all.

The Problem

Storing all files the same way means you pay the same price and wait the same time to open a file, even if you rarely use it. This wastes money and slows down your work. Manually moving files between different storage types is confusing and easy to forget.

The Solution

Storage tiers like Hot, Cool, and Archive automatically organize your files based on how often you use them. Hot is for daily use, Cool for occasional access, and Archive for long-term storage. This saves money and keeps your files ready when you need them.

Before vs After

✗ Before

Store all files in one folder, pay same cost and speed for all

✓ After

Use Hot tier for daily files, Cool for rare files, Archive for long-term files

What It Enables

You can save money and speed up access by storing data in the right place based on how often you use it.

Real Life Example

A company keeps customer support files in Hot storage for quick access, old invoices in Cool storage, and yearly backups in Archive storage to save costs.

Key Takeaways

Manual storage wastes money and time.

Storage tiers organize data by usage frequency.

This leads to cost savings and better performance.

Practice

1. Which Azure Storage tier is best for data that you need to access frequently and quickly?

easy

A. Premium tier

B. Cool tier

C. Archive tier

D. Hot tier

Solution

1. Step 1: Understand storage tier purposes

   The Hot tier is designed for data that is accessed often and requires fast retrieval.

2. Step 2: Compare with other tiers

   Cool tier is for infrequent access, Archive is for rarely accessed data, and Premium is a performance option but not a tier for access frequency.

3. Final Answer:

   Hot tier -> Option D

4. Quick Check:

   Frequent access = Hot tier [OK]

Hint: Hot tier = frequent access, fastest retrieval [OK]

Common Mistakes:

• Confusing Cool tier with Hot tier
• Thinking Archive tier is for frequent access
• Assuming Premium tier is a storage access tier

2. Which of the following is the correct way to specify the Archive tier for a blob in Azure Storage using Azure CLI?

easy

A. az storage account set-tier --tier Archive

B. az storage blob set-tier --tier Hot

C. az storage blob set-tier --tier Archive

D. az storage blob update --tier Cool

Solution

1. Step 1: Identify correct command for blob tier

   The command to set a blob's tier is az storage blob set-tier.

2. Step 2: Choose correct tier parameter

   To set the Archive tier, use --tier Archive. Setting tier on storage account level is invalid.

3. Final Answer:

   az storage blob set-tier --tier Archive -> Option C

4. Quick Check:

   Blob tier set with az storage blob set-tier [OK]

Hint: Use az storage blob set-tier for Archive tier [OK]

Common Mistakes:

• Trying to set tier on storage account instead of blob
• Using wrong command like az storage blob update
• Confusing tier names or casing

3. Consider this Azure Storage blob lifecycle rule snippet:

{
  "rules": [
    {
      "name": "moveToCool",
      "type": "Lifecycle",
      "definition": {
        "actions": {
          "baseBlob": {
            "tierToCool": { "daysAfterModificationGreaterThan": 30 }
          }
        },
        "filters": { "blobTypes": ["blockBlob"] }
      }
    }
  ]
}

What happens to blobs older than 30 days?

medium

A. They are moved to Hot tier

B. They are moved to Cool tier

C. They are deleted

D. They are moved to Archive tier

Solution

1. Step 1: Analyze lifecycle rule action

   The rule specifies tierToCool for blobs modified more than 30 days ago.

2. Step 2: Understand effect on blobs

   Blobs older than 30 days are automatically moved to the Cool tier to save cost.

3. Final Answer:

   They are moved to Cool tier -> Option B

4. Quick Check:

   30+ days old blobs -> Cool tier [OK]

Hint: tierToCool means move blobs older than X days to Cool [OK]

Common Mistakes:

• Assuming blobs move to Archive instead of Cool
• Thinking blobs are deleted by this rule
• Confusing tierToCool with tierToHot

4. You try to set the Archive tier on an entire Azure Storage account but get an error. What is the likely cause?

medium

A. Archive tier can only be set on individual blobs, not on the whole account

B. You must enable Archive tier feature in the portal first

C. Archive tier requires Premium storage account type

D. Archive tier is only for file shares, not blobs

Solution

1. Step 1: Recall Archive tier scope

   Archive tier is applied per blob, not at the storage account level.

2. Step 2: Understand error cause

   Trying to set Archive tier on the whole account causes an error because it's unsupported.

3. Final Answer:

   Archive tier can only be set on individual blobs, not on the whole account -> Option A

4. Quick Check:

   Archive tier scope = per blob [OK]

Hint: Archive tier applies only to blobs, not entire account [OK]

Common Mistakes:

• Thinking Archive tier needs special enablement
• Assuming Archive tier requires Premium account
• Confusing Archive tier with file share tiers

5. A company stores large video files that are rarely accessed but must be retained for years. They want to minimize storage costs but can tolerate hours of retrieval delay. Which Azure Storage tier strategy should they use?

hard

A. Store videos directly in Archive tier

B. Store videos in Cool tier and move to Archive after 90 days

C. Store videos in Hot tier for fast access

D. Store videos in Premium tier for best performance

Solution

1. Step 1: Identify access frequency and cost needs

   Videos are rarely accessed and cost minimization is priority, so Archive tier fits best.

2. Step 2: Consider retrieval delay tolerance

   Archive tier retrieval can take hours, which is acceptable here.

3. Step 3: Evaluate other options

   Hot tier is costly, Cool tier is more expensive than Archive, Premium is for performance, not cost saving.

4. Final Answer:

   Store videos directly in Archive tier -> Option A

5. Quick Check:

   Rare access + low cost = Archive tier [OK]

Hint: Rarely accessed + low cost = Archive tier [OK]

Common Mistakes:

• Choosing Hot or Premium tier for rarely accessed data
• Using Cool tier without moving to Archive
• Ignoring retrieval delay tolerance