Amazon S3 — Simple Storage Service
Virtually unlimited, durable and low-cost object storage. The foundation of data lakes, backups and the most resilient websites on AWS.
What is Amazon S3?
Amazon S3 (Simple Storage Service) is AWS's object storage service: it stores files —images, videos, backups, logs, datasets— as objects inside containers called buckets, reachable via a URL or API. It is designed for 99.999999999% durability (eleven nines), so your data survives hardware failures without you managing any storage servers.
Where S3 stands out is cost control through its storage classes. S3 Standard serves frequently accessed data; S3 Intelligent-Tiering automatically moves each object to the cheapest tier based on its usage pattern, with no retrieval penalty; and S3 Glacier and Glacier Deep Archive keep long-term archival data at a fraction of the cost. Lifecycle policies automate that whole journey —from hot to cold— with no manual work.
Combined with Amazon CloudFront, S3 forms one of the most optimal and resilient architectures to deliver a website: S3 stores the files with eleven nines of durability and CloudFront serves them cached from hundreds of edge points of presence. There are no web servers to maintain or to go down, cost is low, and the site is fast and very hard to take down, even under traffic spikes.
What Amazon S3 is used for
Resilient web delivery (S3 + CloudFront)
Serve static sites and assets from S3 behind CloudFront: fast, cheap, with no servers to go down.
Data lake
Centralize raw and processed data for analytics and AI, queryable directly with services like Athena or Redshift.
Backups and disaster recovery
Durable, versioned backups with cross-region replication for business continuity.
Cost optimization via tiering
Intelligent-Tiering and Glacier so each piece of data pays only what its access frequency warrants.
Compliance archiving
Immutable retention (Object Lock) for regulatory data that must be kept unaltered.
Amazon S3 with an AWS partner
At Caleidos we design your storage architecture on S3 for your use case —data lake, backups or web delivery— with the right storage class, tiering and lifecycle policies to control cost. When your site is business-critical, we combine S3 + CloudFront and add multi-region resilience so it stays available even if an entire region fails.
Explore Cloud Foundations →Frequently asked questions
- What if my website is critical to my business?
- A critical website cannot depend on a single server or a single region. The recommended architecture is S3 + CloudFront —which already removes web servers as a point of failure— and, for maximum continuity, a multi-region strategy: if one AWS region fails, traffic is served from another without the user noticing. At Caleidos we design that level of resilience to the RTO/RPO your business needs.
- What is the difference between the S3 classes (Standard, Intelligent-Tiering, Glacier)?
- Standard is for frequently accessed data; Intelligent-Tiering automatically moves each object to the cheapest tier based on usage, with no decisions on your part; and Glacier / Glacier Deep Archive are for long-term archiving at very low cost. Lifecycle policies automate moving between them.
- Is it safe to store sensitive data in S3?
- Yes, when configured properly: encryption at rest, least-privilege IAM access, public access blocking and, for regulated data, Object Lock. Misconfigured permissions are the most common —and avoidable— mistake.
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