Amazon S3 Bucket Evolution and the New 50 TB Object Limit

Overview

Amazon S3 (Simple Storage Service) has been one of the most reliable, secure, and scalable object storage services since its launch. Over the years, AWS has significantly enhanced S3’s security posture, performance capabilities, and operational features. These enhancements have created a notable difference between old Amazon S3 buckets (created several years ago) and new Amazon S3 buckets (created under modern AWS defaults).

In addition to the security and configuration changes, AWS recently announced a major upgrade: support for storing objects up to 50 TB, a 10x increase from the previous 5 TB limit. This enhancement applies to all Amazon S3 storage classes and greatly simplifies handling extremely large datasets such as high-resolution videos, seismic files, machine learning training datasets, and archival workloads.

This blog walks through the key differences between old and new Amazon S3 buckets, outlines the features that must be updated to stay aligned with AWS best practices, and explains how the new 50 TB object support impacts storage strategies.

Introduction

Older Amazon S3 buckets were created during a time when AWS had a more flexible and permissive default security model. Features such as Block Public Access, encryption by default, and ACL disabling did not exist. As a result, many organizations today still operate outdated Amazon S3 buckets that pose potential risks or inefficiencies.

Today, Amazon S3 buckets are created with a “secure-by-default” approach. New buckets automatically block public access, disable ACLs, enable default encryption, and enforce modern policy structures. Additionally, Amazon S3 has matured to support deep integrations, including lifecycle policies, replication, access logging, AWS CloudTrail data events, and analytics features.

This blog highlights the purpose behind these differences and explains how users can modernize old Amazon S3 buckets to match today’s standards.

Purpose of Comparison

The primary goal of comparing old and new Amazon S3 buckets is to help organizations:

• Identify outdated or risky configurations
• Modernize legacy buckets to follow AWS’s secure-by-default posture
• Align all buckets with best practices for security, cost optimization, and governance
• Understand how the 50 TB object support impacts data lake and AI/ML workloads
• Ensure compliance across cloud storage environments

By understanding these changes, teams can bring consistency across their Amazon S3 environments and reduce the risk of misconfigurations or data exposure.

Prerequisites

Before updating or comparing Amazon S3 buckets, ensure the following:

Required AWS IAM Permissions:

• s3:GetBucketPolicy
• s3:PutBucketPolicy
• s3:GetBucketAcl
• s3:PutBucketAcl
• s3:PutBucketEncryption
• s3:PutLifecycleConfiguration
• s3:PutBucketPublicAccessBlock

Recommended Knowledge

• Basics of AWS IAM
• Amazon S3 storage classes and lifecycle rules
• Server-side encryption (SSE-S3 / SSE-KMS)
• Logging & monitoring tools like AWS CloudTrail and AWS Config

Having these prerequisites ensures a smooth and secure update process.

Implementation Steps

Reviewing Bucket Security Settings

Start by auditing existing Amazon S3 buckets. Older buckets might still use ACLs, lack encryption, or even allow public access. Review:

• ACL settings
• Bucket policies
• Encryption status
• Public access configuration
• Lifecycle rules
• Logging and monitoring
• Object size requirements for large-data workloads

This baseline helps identify what needs modernization.

Enabling Block Public Access

New buckets automatically block all public access, but older buckets may still allow public ACLs or bucket policies. Enable the following:

• Block public ACLs
• Block public bucket policies
• Ignore public ACLs
• Restrict public bucket policies

This is essential to prevent accidental data exposure, one of the most common cloud security risks.

Disabling ACLs (if applicable)

AWS now recommends disabling ACLs entirely unless absolutely necessary. New buckets come with ACLs disabled.
Legacy buckets using ACLs should be transitioned to AWS IAM-based access controls for simplicity and enhanced security.

Enabling Default Encryption

All new Amazon S3 buckets are automatically encrypted at rest using SSE-S3. Older buckets may not.
Enable default encryption to ensure all objects, including extremely large objects up to 50 TB, are encrypted without manual configuration.

Updating Bucket Policies

Modern bucket policies enforce better structural standards and security conditions. Update old policies to:

• Enforce HTTPS-only access
• Restrict cross-account permissions
• Remove wildcard (*) permissions
• Eliminate legacy ACL-based access
• Improve readability and maintainability

This ensures consistent governance and compliance.

Implementing Lifecycle Rules

Lifecycle rules help optimize cost and automate data transitions. Today, lifecycle policies work seamlessly even for very large objects.
For older buckets, add:

• Intelligent-Tiering transitions
• Archival policies to Amazon S3 Glacier
• Automated deletion of expired objects

This reduces storage cost and improves data organization.

Configuring Logging & Monitoring

Modern Amazon S3 governance requires strong observability:

• Enable Amazon S3 Access Logs
• Enable AWS CloudTrail Data Events
• Use AWS Config to detect risky changes automatically

These monitoring features strengthen auditability and security.

Advantages

Updating old buckets to modern standards offers several benefits:

Security & Governance

• Stronger data protection with encryption-by-default
• Reduced attack surface via Block Public Access
• Clear and manageable IAM-based permissions

Performance & Scalability

• Improved transfer speeds when using the AWS Common Runtime (CRT) and Amazon S3 Transfer Manager
• Ability to upload and download massive objects (up to 50 TB) efficiently
• Simplified workflows for large media files, AI datasets, and scientific workloads

Cost Optimization

• Automated lifecycle transitions reduce long-term storage costs
• Intelligent-Tiering adjusts storage tiers based on usage
• Better control over data retention policies

Reliability & Flexibility

• Full support for 50 TB objects across all S3 storage classes
• Compatibility with all Amazon S3 features, including Replication and Glacier
• Streamlined access management with disabled ACLs

Overall, modernizing Amazon S3 buckets yields stronger security, improved performance, and reduced operational overhead.

Conclusion

Amazon S3 has grown from a simple object storage service into a highly secure and scalable platform capable of supporting enterprise-grade workloads. The differences between old and new Amazon S3 buckets highlight AWS’s commitment to a secure-by-default environment.

The new 50 TB object support further elevates Amazon S3’s capabilities, enabling customers to store extremely large datasets without fragmentation. This update benefits industries that handle massive files, such as media production, AI/ML, geospatial analysis, and scientific research.

Organizations should regularly audit and modernize older buckets to adopt today’s best practices. Doing so strengthens security, enhances performance, and ensures full compatibility with AWS’s latest features.

Modern Amazon S3 buckets offer the ideal foundation for scalable, secure, and cost-efficient cloud storage.

Drop a query if you have any questions regarding Amazon S3 and we will get back to you quickly.

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