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S3 Buckets and Objects

Buckets

  • Amazon S3 allows people to store objects (files) in buckets (directories)
  • Buckets must have a globally unique name
  • Buckets are defined at the region level
  • Naming convention
    • no uppercase
    • no underscore
    • 3-63 characters long
    • not an IP
    • must start with lowercase letter or number

Objects

  • Objects (files) have a key
  • The key is full path:
    • s3://my-bucket/my_file.txt
    • s3://my-bucket/my_folder1/another_folder/my_name.txt
  • The key is composed of prefix + object name
    • prefix: my_folder1/another_folder
    • name: my_name.txt
  • There's no concept of "directories" within buckets. Although the UI will trick you to think otherwise.
  • Just keys with very long names that contain slashes.
  • Object values are content of the body:
    • Max object size is 5 TB
    • If uploading more than 5 GB, must use multi-part upload
  • Metadata (list of text key / value pairs - system or user metadata)
  • Tags (unicode key / value pair - up to 10) - useful for security / lifecycle
  • Version ID (if versioning is enabled)