Amazon Simple Storage Service
Developer Guide (API Version 2006-03-01)

Using Reduced Redundancy Storage

Amazon S3 stores objects according to their storage class. It assigns the storage class to an object when it is written to Amazon S3. You can assign objects a specific storage class (STANDARD, STANDARD_IA, REDUCED_REDUNDANCY) only when you write the objects to an Amazon S3 bucket or when you copy objects that are already stored in Amazon S3. Standard is the default storage class. For information about storage classes, see Storage Classes.

Reduced redundancy storage is designed to provide 99.99% durability of objects over a given year. This durability level corresponds to an average annual expected loss of 0.01% of objects. For example, if you store 10,000 objects using the RRS option, you can, on average, expect to incur an annual loss of a single object per year (0.01% of 10,000 objects).


This annual loss represents an expected average and does not guarantee the loss of less than 0.01% of objects in a given year.

Reduced redundancy storage stores objects on multiple devices across multiple facilities, providing 400 times the durability of a typical disk drive, but it does not replicate objects as many times as Amazon S3 standard storage. In addition, reduced redundancy storage is designed to sustain the loss of data in a single facility.

If an object in reduced redundancy storage has been lost, Amazon S3 will return a 405 error on requests made to that object. Amazon S3 also offers notifications for reduced redundancy storage object loss: you can configure your bucket so that when Amazon S3 detects the loss of an RRS object, a notification will be sent through Amazon Simple Notification Service (Amazon SNS). You can then replace the lost object. To enable notifications from the Amazon S3 console, choose the Properties tab for your bucket, and then choose Events.

Latency and throughput for reduced redundancy storage are the same as for standard storage. For more information about cost considerations, see Amazon S3 Pricing.