S3 Storage Classes:

• A storage class represents the "classification" assigned to each Object in S3. Current Storage Class types include:
  • Standard
  • Reduced Redundancy Storage(RRS)
  • Infrequent Access (S3-IA)
  • Glacier
• Each storage class has varying attributes that dictate things like:
  • Storage cost
  • Object availability
  • Object durability
  • Frequency of access (to the object)

Standard:

• Designed for general, all-purpose storage.
• Is the default storage option.
• 99.999999999% object durability ("eleven nines").
• 99.99% object availability.
• Is the most expensive storage class.

Reduced Redundancy Storage (RRS):

• Designed for non-critical, reproducible objects.

• 99.99% object durability.

• 99.99% object availability.

• Is less expensive than the standard storage class.

Infrequent Access (S3-IA):

• Designed for objects that you do not frequently access, but must be immediately available when accessed.

• 99.999999999% object durability.

• 99.90% object availability.

• Is less expensive than the standard/RRS storage classes.

Glacier:

• Designed for long-term archival storage (not to be used for backups).

• May take serveral hours for objects stored in Glacier to be retrieved.

• 99.999999999% object durability.

• Is the cheapest S3 storage class (very low cost).

More on Glacier:

• Amazon Glacier is an archival storage type.
• Used for data that is NOT accessed frequently.
• "Check out" and "check in jobs" can take several hours, meaning how long it can take for the data to be changed and/or retrieved.
• Integrates with Amazon S3 lifecycle policies for easy archiving.
• Very inexpensive and cost effective archival storage solution.
• Glacier should NOT be used as a backup solution.

NOTE: Glacier now offers three levels of data retrieval (pricing varies):

• Expedited: 1-5 minutes.
• Standard: 3-5 hours.
• Bulk: 5-12 hours.