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

Storage Classes

Each object in Amazon S3 has a storage class associated with it. For example, if you list the objects in an S3 bucket, the console shows the storage class for all the objects in the list.


        Shows example of storage classes in the Amazon S3 console.

Amazon S3 offers a range of storage classes for the objects that you store. You choose a class depending on your use case scenario and performance access requirements. All of these storage classes offer high durability.

Storage Classes for Frequently Accessed Objects

For performance-sensitive use cases (those that require millisecond access time) and frequently accessed data, Amazon S3 provides the following storage classes:

  • STANDARD—The default storage class. If you don't specify the storage class when you upload an object, Amazon S3 assigns the STANDARD storage class.

     

  • REDUCED_REDUNDANCY—The Reduced Redundancy Storage (RRS) storage class is designed for noncritical, reproducible data that can be stored with less redundancy than the STANDARD storage class.

    Important

    We recommend that you not use this storage class. The STANDARD storage class is more cost effective.

    For durability, RRS objects have an average annual expected loss of 0.01% of objects. If an RRS object is lost, when requests are made to that object, Amazon S3 returns a 405 error.

Storage Class That Automatically Optimizes Frequently and Infrequently Accessed Objects

The INTELLIGENT_TIERING storage class is designed to optimize storage costs by automatically moving data to the most cost-effective storage access tier, without performance impact or operational overhead. INTELLIGENT_TIERING delivers automatic cost savings by moving data on a granular object level between two access tiers, a frequent access tier and a lower-cost infrequent access tier, when access patterns change. The INTELLIGENT_TIERING storage class is ideal if you want to optimize storage costs automatically for long-lived data when access patterns are unknown or unpredictable.

The INTELLIGENT_TIERING storage class stores objects in two access tiers: one tier that is optimized for frequent access and another lower-cost tier that is optimized for infrequently accessed data. For a small monthly monitoring and automation fee per object, Amazon S3 monitors access patterns of the objects in the INTELLIGENT_TIERING storage class and moves objects that have not been accessed for 30 consecutive days to the infrequent access tier. There are no retrieval fees when using the INTELLIGENT_TIERING storage class. If an object in the infrequent access tier is accessed, it is automatically moved back to the frequent access tier. No additional tiering fees apply when objects are moved between access tiers within the INTELLIGENT_TIERING storage class.

Note

The INTELLIGENT_TIERING storage class is suitable for objects larger than 128 KB that you plan to store for at least 30 days. If the size of an object is less than 128 KB, it is not eligible for auto-tiering. Smaller objects can be stored, but they are always charged at the frequent access tier rates in the INTELLIGENT_TIERING storage class. If you delete an object before the 30-day minimum, you are charged for 30 days. For pricing information, see Amazon S3 Pricing.

Storage Classes for Infrequently Accessed Objects

The STANDARD_IA and ONEZONE_IA storage classes are designed for long-lived and infrequently accessed data. (IA stands for infrequent access.) STANDARD_IA and ONEZONE_IA objects are available for millisecond access (similar to the STANDARD storage class). Amazon S3 charges a retrieval fee for these objects, so they are most suitable for infrequently accessed data. For pricing information, see Amazon S3 Pricing.

For example, you might choose the STANDARD_IA and ONEZONE_IA storage classes:

  • For storing backups.

     

  • For older data that is accessed infrequently, but that still requires millisecond access. For example, when you upload data, you might choose the STANDARD storage class, and use lifecycle configuration to tell Amazon S3 to transition the objects to the STANDARD_IA or ONEZONE_IA class. For more information about lifecycle management, see Object Lifecycle Management.

Note

The STANDARD_IA and ONEZONE_IA storage classes are suitable for objects larger than 128 KB that you plan to store for at least 30 days. If an object is less than 128 KB, Amazon S3 charges you for 128 KB. If you delete an object before the 30-day minimum, you are charged for 30 days. For pricing information, see Amazon S3 Pricing.

These storage classes differ as follows:

  • STANDARD_IA—Amazon S3 stores the object data redundantly across multiple geographically separated Availability Zones (similar to the STANDARD storage class). STANDARD_IA objects are resilient to the loss of an Availability Zone. This storage class offers greater availability, durability, and resiliency than the ONEZONE_IA class.

     

  • ONEZONE_IA—Amazon S3 stores the object data in only one Availability Zone, which makes it less expensive than STANDARD_IA. However, the data is not resilient to the physical loss of the Availability Zone resulting from disasters, such as earth quakes and floods. The ONEZONE_IA storage class is as durable as STANDARD_IA, but it is less available and less resilient. For a comparison of storage class durability and availability, see the Durability and Availability table at the end of this section. For pricing, see Amazon S3 Pricing.

We recommend the following:

  • STANDARD_IA—Use for your primary or only copy of data that can't be recreated.

  • ONEZONE_IA—Use if you can recreate the data if the Availability Zone fails, and for object replicas when setting cross-region replication (CRR).

GLACIER Storage Class

The GLACIER storage class is suitable for archiving data where data access is infrequent. This storage class offers the same durability and resiliency as the STANDARD storage class.

You can set the storage class of an object to GLACIER in the same ways that you do for the other storage classes as described in the section Setting the Storage Class of an Object. However, the GLACIER archived objects are not available for real-time access. You must first restore the GLACIER objects before you can access them (STANDARD, RRS, STANDARD_IA, and ONEZONE_IA objects are available for anytime access). For more information, see Restoring Archived Objects.

Important

When you choose the GLACIER storage class, Amazon S3 uses the low-cost Glacier service to store the objects. Although the objects are stored in Glacier, these remain Amazon S3 objects that you manage in Amazon S3, and you cannot access them directly through Glacier.

To learn more about the Glacier service, see the Amazon S3 Glacier Developer Guide.

Comparing the Amazon S3 Storage Classes

The following table compares the storage classes.

Storage Class Designed for Durability (designed for) Availability (designed for) Availability Zones Min storage duration Min billable object size Other Considerations

STANDARD

Frequently accessed data

99.999999999%

99.99%

>= 3

None

None

None

STANDARD_IA

Long-lived, infrequently accessed data

99.999999999%

99.9%

>= 3

30 days

128 KB

Per GB retrieval fees apply.

INTELLIGENT_TIERING

Long-lived data with changing or unknown access patterns

99.999999999%

99.9%

>= 3

30 days

None

Monitoring and automation fees per object apply. No retrieval fees.

ONEZONE_IA

Long-lived, infrequently accessed, non-critical data

99.999999999%

99.5%

1

30 days

128 KB

Per GB retrieval fees apply. Not resilient to the loss of the Availability Zone.

GLACIER

Long-term data archiving with retrieval times ranging from minutes to hours 99.999999999%

99.99% (after you restore objects)

>= 3

90 days

None

Per GB retrieval fees apply. You must first restore archived objects before you can access them. For more information, see Restoring Archived Objects.

RRS (Not recommended)

Frequently accessed, non-critical data

99.99%

99.99%

>= 3

None

None

None

All of the storage classes except for ONEZONE_IA are designed to be resilient to simultaneous complete data loss in a single Availability Zone and partial loss in another Availability Zone.

In addition to the performance requirements of your application scenario, consider price. For storage class pricing, see Amazon S3 Pricing.

Setting the Storage Class of an Object

Amazon S3 APIs support setting (or updating) the storage class of objects as follows:

  • When creating a new object, you can specify its storage class. For example, when creating objects using the PUT Object, POST Object, and Initiate Multipart Upload APIs, you add the x-amz-storage-class request header to specify a storage class. If you don't add this header, Amazon S3 uses STANDARD, the default storage class.

     

  • You can also change the storage class of an object that is already stored in Amazon S3 by making a copy of the object using the PUT Object - Copy API. You copy the object in the same bucket using the same key name and specify request headers as follows:

    • Set the x-amz-metadata-directive header to COPY.

    • Set the x-amz-storage-class to the storage class that you want to use.

    In a versioning-enabled bucket, you cannot change the storage class of a specific version of an object. When you copy it, Amazon S3 gives it a new version ID.

     

  • You can direct Amazon S3 to change the storage class of objects by adding a lifecycle configuration to a bucket. For more information, see Object Lifecycle Management.

     

  • When setting up a Cross-region replication (CRR) configuration you can set the storage class for replicated objects. For more information, see Replication Configuration Overview.

To create and update object storage classes, you can use the Amazon S3 console, AWS SDKs, or the AWS Command Line Interface (AWS CLI). Each uses the Amazon S3 APIs to send requests to Amazon S3.