S3 Review

S3

• Simple Storage Service (S3): Key-value store for object storage at scale
  • Bucket + Key : Object
• Object Storage: Any sequence of bytes (photos, videos, source code, ...)
• Durability: 99.999999999%
  • Replicated across data centers and AZs
• Features: ACLs, Metadata, Versioning, Encryption, ...

When to use S3?

• S3 Use Cases: Think "file storage"
  • Object Size: support for large files (up to 5TB)
  • Integration with CloudFront CDN
  • Support for archiving data (to Glacier)
  • examples: website static content (HTML/CSS/etc.), log files
• Non-S3 Use Cases: Databases -- think "queryable data"
  • Object Size: Limited (f.e., 400Kb for DynamoDB)
  • DBMS guarantees
    • Support for indexes for querying
  • Faster read/writes
  • examples: user profile data, credentials

S3 Concepts

• Object: Fundamental entity in S3
  • Consists of object data + metadata
  • Metadata: name-value pairs that describe the object
    • date last modified, content-type, etc.
• Bucket: Container for objects stored in S3
  • Bucket name must be globally unique
  • Can store unlimited objects
• Key: Unique identifier of objects within buckets

Example: https://s3.amazonaws.com/cmsc389l/apple.png

S3 Atomicity

• Atomic: Reads to a previously updated object will return either the updated object or the previous object. Never partial or corrupted data.

S3 Consistency

• Eventual Consistency: Update and delete operations are not available until fully replicated.
  • For new keys, reads have read-after-write consistency

S3 Storage Types

* : Excludes the usual data storage (per-GB), external bandwidth (GB/month), and API call charges

CloudFront

CloudFront Concepts

• Content Delivery Networks (CDN): a globally-distributed network of proxy servers which cache content
  • Use cases: web streaming, static content acceleration

CDN Metrics

• Latency: Time taken until the first byte is downloaded
• Data Transfer Rates: Rate at which data is transferred to the client
• Cache Hit Ratio: The percent of requests where the data can be retrieved from the cache

CloudFront Concepts

• Edge Locations: Proxy server in the CloudFront network
• Regional Edge Caches: Proxy servers that intermediates between origin server and edge locations.

CloudFront Concepts

• Origin Server: The definitive store of content that CloudFront will accelerate (f.e., S3 or EC2 web server)
• Distribution: Configuration specifying your origin server, cache invalidation rules, etc. 
  • Shared with edge locations

CloudFront Costs

• Transfer from CloudFront to Internet: $0.085 / GB
  • ​Varies by region and throughput
    • Drops to $0.020 / GB
• Transfer from AWS (S3, etc.) to CloudFront: Free
• Per-request fee: $0.01 / 10k requests

Worksheet: CloudFront

Complete the worksheet on CloudFront.