S3 Glacier: A Step-by-Step Guide to Archiving Your Data

 

S3 Glacier: A Step-by-Step Guide to Archiving Your Data

Question

"I have a lot of old files I need to keep for compliance reasons, but I don't need to access them very often. They're taking up too much space on my S3 Standard storage, which is getting expensive. How can I move these files to a cheaper storage option while still being able to retrieve them if needed?"

Clarifying the Issue

You're looking for a cost-effective way to store archival data that you don’t need frequently but want to retrieve when necessary. S3 Standard is excellent for active storage but costly for long-term retention.

Why It Matters

Managing storage costs is crucial, especially when dealing with large datasets. By transitioning data to S3 Glacier, you can significantly reduce your AWS bill while ensuring compliance with data retention policies. Glacier provides a secure, durable, and low-cost solution for long-term data archiving.

Key Terms

• S3 Glacier: A low-cost AWS storage class designed for long-term archival.
• Storage Class: Different Glacier tiers with varying retrieval times and costs.
• Retrieval: The process of restoring data from Glacier to S3 for access.
• Restore Job: A request to temporarily make Glacier data available in S3.
• Lifecycle Policies: Automated rules that transition objects between storage classes over time.
• AWS CLI: The AWS Command Line Interface, a tool for managing AWS services via commands.

Steps at a Glance

1. Choose the appropriate Glacier storage class.
2. Move your files to Glacier (console, CLI, or lifecycle policies).
3. Initiate a restore job when you need to access archived files.

Detailed Steps

1. Choosing the Right Glacier Storage Class

AWS offers three Glacier storage tiers:

• Glacier Instant Retrieval: Millisecond access times, but the highest Glacier cost.
• Glacier Flexible Retrieval: Cheaper than Instant, but retrieval takes minutes to hours.
• Glacier Deep Archive: The lowest cost, but retrieval takes 12–48 hours.

💡 Tip: If you need instant access, Instant Retrieval is best. Otherwise, Flexible Retrieval or Deep Archive is far more cost-effective.

2. Moving Your Files to Glacier

Option 1: Using the AWS Management Console

For small datasets, you can manually select files in your S3 bucket and choose a Glacier storage class.

Option 2: Using the AWS CLI (Best for Automation & Large Datasets)

Copy a Single File to Glacier

Bash

aws s3 cp s3://your-bucket/old-file.zip s3://your-glacier-bucket/ \
    --storage-class GLACIER_FLEXIBLE_RETRIEVAL

Copy an Entire Folder to Glacier

Bash

aws s3 cp s3://your-bucket/old-files/ s3://your-glacier-bucket/ \
    --storage-class GLACIER_FLEXIBLE_RETRIEVAL --recursive

Option 3: Using S3 Lifecycle Policies (Recommended for Automation)

A better long-term approach is to automate Glacier transitions using Lifecycle Policies.

Example JSON Policy (Moves Files Older than 30 Days to Glacier)

JSON

{
    "Rules": [
        {
            "ID": "MoveToGlacier",
            "Prefix": "old-files/",
            "Status": "Enabled",
            "Transitions": [
                {
                    "Days": 30,
                    "StorageClass": "GLACIER_FLEXIBLE_RETRIEVAL"
                }
            ]
        }
    ]
}

Apply This Policy via CLI

Bash

aws s3api put-bucket-lifecycle-configuration --bucket your-bucket \
    --lifecycle-configuration file://lifecycle.json

💡 Tip: Lifecycle policies automatically move files to Glacier, reducing manual effort and human error.

3. Retrieving Your Files (Restoring)

Step 1: Initiate a Restore Job

When you need to access Glacier data, you must submit a restore request.

Restore a File via AWS CLI

Bash

aws s3api restore-object --bucket your-bucket --key old-file.zip \
    --restore-request '{"Days":5,"GlacierJobParameters":{"Tier":"Standard"}}'

• Days: How long the restored file remains available in S3 (before returning to Glacier).
• Tier: Choose from Expedited, Standard, or Bulk (faster tiers cost more).

Step 2: Download the Restored Data

Once the restore job completes, download the file like any other S3 object.

Bash

aws s3 cp s3://your-bucket/old-file.zip ./

💡 Note: Restored files don’t automatically stay in Standard storage—they return to Glacier after the specified days unless copied elsewhere.

Closing Thoughts

S3 Glacier is an excellent solution for reducing storage costs while maintaining long-term data retention. By choosing the right storage class, automating with lifecycle policies, and understanding retrieval options, you can optimize your AWS storage strategy.

Key Takeaways

✅ Use Glacier Deep Archive for the lowest cost if you can wait 12–48 hours.

✅ Use Lifecycle Policies for automated and cost-efficient transitions.

✅ Plan for retrieval times and fees—faster access costs more.

For official AWS documentation:

• AWS Glacier Documentation
• AWS CLI Documentation
• S3 Lifecycle Policies

What’s Next?

We'll continue blogging about AWS S3 Glacier and other AWS services, covering cost optimization, security best practices, and advanced use cases. Stay tuned for more insights!

Let us know if you have any questions or AWS challenges—we’re here to help! 

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