Understanding and managing Amazon S3 storage classes - Amazon Simple Storage Service
Frequently accessed objectsAutomatically optimizing data with changing or unknown access patternsInfrequently accessed objectsRarely accessed objectsAmazon S3 on OutpostsComparing storage classes

Understanding and managing Amazon S3 storage classes

Each object in Amazon S3 has a storage class associated with it. By default, objects in S3 are stored in the S3 Standard storage class, however Amazon S3 offers a range of other storage classes for the objects that you store. You choose a class depending on your use case scenario and performance access requirements. Choosing a storage class designed for your use case lets you optimize storage costs, performance, and availability for your objects. All of these storage classes offer high durability.

The following sections provide details of the various storage classes and how to set the storage class for your objects.

Topics

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:

  • S3 Standard – The default storage class. If you don't specify the storage class when you upload an object, Amazon S3 assigns the S3 Standard storage class. To help you optimize costs between S3 Standard and S3 Standard-IA you can use Amazon S3 analytics – Storage Class Analysis.

  • S3 Express One Zone – Amazon S3 Express One Zone is a high-performance, single-zone Amazon S3 storage class that is purpose-built to deliver consistent, single-digit millisecond data access for your most latency-sensitive applications. S3 Express One Zone is the lowest latency cloud object storage class available today, with data access speed up to 10x faster and with request costs 50 percent lower than S3 Standard. With S3 Express One Zone, your data is redundantly stored on multiple devices within a single Availability Zone. For more information, see Directory buckets and S3 Express One Zone.

  • Reduced Redundancy – The Reduced Redundancy Storage (RRS) storage class is designed for noncritical, reproducible data that can be stored with less redundancy than the S3 Standard storage class.

    Important

    We recommend not using this storage class. The S3 Standard storage class is more cost-effective.

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

Storage class for automatically optimizing data with changing or unknown access patterns

S3 Intelligent-Tiering is an Amazon S3 storage class that's designed to optimize storage costs by automatically moving data to the most cost-effective access tier, without performance impact or operational overhead. S3 Intelligent-Tiering is the only cloud storage class that delivers automatic cost savings by moving data on a granular object level between access tiers when access patterns change. S3 Intelligent-Tiering is the ideal storage class when you want to optimize storage costs for data that has unknown or changing access patterns. There are no retrieval fees for S3 Intelligent-Tiering.

For a small monthly object monitoring and automation fee, S3 Intelligent-Tiering monitors access patterns and automatically moves objects that have not been accessed to lower-cost access tiers. S3 Intelligent-Tiering delivers automatic storage cost savings in three low-latency and high-throughput access tiers. For data that can be accessed asynchronously, you can choose to activate automatic archiving capabilities within the S3 Intelligent-Tiering storage class. S3 Intelligent-Tiering is designed for 99.9% availability and 99.999999999% durability.

S3 Intelligent-Tiering automatically stores objects in three access tiers:

  • Frequent Access – Objects that are uploaded or transitioned to S3 Intelligent-Tiering are automatically stored in the Frequent Access tier.

  • Infrequent Access – S3 Intelligent-Tiering moves objects that have not been accessed in 30 consecutive days to the Infrequent Access tier.

  • Archive Instant Access – With S3 Intelligent-Tiering, any existing objects that have not been accessed for 90 consecutive days are automatically moved to the Archive Instant Access tier.

In addition to these three tiers, S3 Intelligent-Tiering offers two optional archive access tiers:

  • Archive Access – S3 Intelligent-Tiering provides you with the option to activate the Archive Access tier for data that can be accessed asynchronously. After activation, the Archive Access tier automatically archives objects that have not been accessed for a minimum of 90 consecutive days.

  • Deep Archive Access – S3 Intelligent-Tiering provides you with the option to activate the Deep Archive Access tier for data that can be accessed asynchronously. After activation, the Deep Archive Access tier automatically archives objects that have not been accessed for a minimum of 180 consecutive days.

Note

  • Only activate the Archive Access tier for 90 days if you want to bypass the Archive Instant Access tier. The Archive Access tier delivers slightly lower-cost storage with minute-to-hour retrieval times. The Archive Instant Access tier delivers millisecond access and high-throughput performance.

  • Activate the Archive Access and Deep Archive Access tiers only if your objects can be accessed asynchronously by your application. If the object that you are retrieving is stored in the Archive Access or Deep Archive Access tiers, first restore the object by using RestoreObject.

You can move newly created data to S3 Intelligent-Tiering, setting it as your default storage class. You can also choose to activate one or both of the archive access tiers by using the PutBucketIntelligentTieringConfiguration API operation, the AWS CLI, or the Amazon S3 console. For more information about using S3 Intelligent-Tiering and activating the archive access tiers, see Using S3 Intelligent-Tiering.

To access objects in the Archive Access or Deep Archive Access tiers, you first need to restore them. For more information, see Restoring objects from the S3 Intelligent-Tiering Archive Access and Deep Archive Access tiers.

Note

If the size of an object is less than 128 KB, it is not monitored and not eligible for auto-tiering. Smaller objects are always stored in the Frequent Access tier. For more information about S3 Intelligent-Tiering, see S3 Intelligent-Tiering access tiers.

Storage classes for infrequently accessed objects

The S3 Standard-IA and S3 One Zone-IA storage classes are designed for long-lived and infrequently accessed data. (IA stands for infrequent access.) S3 Standard-IA and S3 One Zone-IA objects are available for millisecond access (similar to the S3 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 S3 Standard-IA and S3 One Zone-IA storage classes to do the following:

  • 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 S3 Standard storage class, and use lifecycle configuration to tell Amazon S3 to transition the objects to the S3 Standard-IA or S3 One Zone-IA class.

    For more information about lifecycle management, see Managing the lifecycle of objects.

Note

The S3 Standard-IA and S3 One Zone-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 end of the 30-day minimum storage duration period, you are charged for 30 days. Objects that are deleted, overwritten, or transitioned to a different storage class before 30 days will incur the normal storage usage charge plus a pro-rated charge for the remainder of the 30-day minimum. For pricing information, see Amazon S3 pricing.

These storage classes differ as follows:

  • S3 Standard-IA – Amazon S3 stores the object data redundantly across multiple geographically separated Availability Zones (similar to the S3 Standard storage class). S3 Standard-IA objects are resilient to the loss of an Availability Zone. This storage class offers greater availability and resiliency than the S3 One Zone-IA class. To help you optimize costs between S3 Standard and S3 Standard-IA you can use Amazon S3 analytics – Storage Class Analysis

  • S3 One Zone-IA – Amazon S3 stores the object data in only one Availability Zone, which makes it less expensive than S3 Standard-IA. However, the data is not resilient to the physical loss of the Availability Zone resulting from disasters, such as earthquakes and floods. The S3 One Zone-IA storage class is as durable as S3 Standard-IA, but it is less available and less resilient. For a comparison of storage class durability and availability, see Comparing the Amazon S3 storage classes at the end of this section. For pricing information, see Amazon S3 pricing.

We recommend the following:

  • S3 Standard-IA – Use for your primary or only copy of data that can't be re-created.

  • S3 One Zone-IA – Use if you can re-create the data if the Availability Zone fails, and for object replicas when configuring S3 Cross-Region Replication (CRR).

Storage classes for rarely accessed objects

The S3 Glacier Instant Retrieval, S3 Glacier Flexible Retrieval, and S3 Glacier Deep Archive storage classes are designed for low-cost, long-term data storage and data archiving. These storage classes require minimum storage durations and retrieval fees making them most effective for rarely accessed data. For more information about S3 Glacier storage classes, see Understanding S3 Glacier storage classes for long-term data storage.

Amazon S3 provides the following S3 Glacier storage classes:

  • S3 Glacier Instant Retrieval – Use for long-term data that's rarely accessed and requires milliseconds retrieval. Data in this storage class is available for real-time access.

  • S3 Glacier Flexible Retrieval – Use for archives where portions of the data might need to be retrieved in minutes. Data in this storage class is archived, and not available for real-time access.

  • S3 Glacier Deep Archive – Use for archiving data that rarely needs to be accessed. Data in this storage class is archived, and not available for real-time access.

Retrieving archived objects

You can set the storage class of an object to S3 Glacier Flexible Retrieval or S3 Glacier Deep Archive 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, S3 Glacier Flexible Retrieval and S3 Glacier Deep Archive objects are archived, and not available for real-time access. For more information, see Understanding archival storage in S3 Glacier Flexible Retrieval and S3 Glacier Deep Archive.

Note

When you use S3 Glacier storage classes, your objects remain in Amazon S3. You can't access them directly through the separate Amazon S3 Glacier service. For information about the Amazon S3 Glacier service, see the Amazon S3 Glacier Developer Guide.

Storage class for Amazon S3 on Outposts

With Amazon S3 on Outposts, you can create S3 buckets on your AWS Outposts resources and store and retrieve objects on-premises for applications that require local data access, local data processing, and data residency. You can use the same API operations and features on AWS Outposts as you do on Amazon S3, including access policies, encryption, and tagging. You can use S3 on Outposts through the AWS Management Console, AWS CLI, AWS SDKs, or REST API.

S3 on Outposts provides a new storage class, S3 Outposts (OUTPOSTS). The S3 Outposts storage class is available only for objects stored in buckets on Outposts. If you try to use this storage class with an S3 bucket in an AWS Region, an InvalidStorageClass error occurs. In addition, if you try to use other S3 storage classes with objects stored in S3 on Outposts buckets, the same error occurs.

Objects stored in the S3 Outposts (OUTPOSTS) storage class are always encrypted by using server-side encryption with Amazon S3 managed encryption keys (SSE-S3). For more information, see Using server-side encryption with Amazon S3 managed keys (SSE-S3).

You can also explicitly choose to encrypt objects stored in the S3 Outposts storage class by using server-side encryption with customer-provided encryption keys (SSE-C). For more information, see Using server-side encryption with customer-provided keys (SSE-C).

Note

S3 on Outposts doesn't support server-side encryption with AWS Key Management Service (AWS KMS) keys (SSE-KMS).

For more information about S3 on Outposts, see What is S3 on Outposts in the Amazon S3 on Outposts User Guide.

Comparing the Amazon S3 storage classes

The following table compares the storage classes, including their availability, durability, minimum storage duration, and other considerations.

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

S3 Standard

Frequently accessed data (more than once a month) with millisecond access

99.999999999%

99.99%

>= 3

None

None

None

S3 Standard-IA

Long-lived, infrequently accessed data (once a month) with millisecond access

99.999999999%

99.9%

>= 3

30 days

128 KB

Per-GB retrieval fees apply.

S3 Intelligent-Tiering

Data with unknown, changing, or unpredictable access patterns

99.999999999%

99.9%

>= 3

None

None

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

S3 One Zone-IA

Recreatable, infrequently accessed data (once a month) with millisecond access

99.999999999%

99.5%

1

30 days

128 KB

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

S3 Express One Zone

Single-digit millisecond data access for latency-sensitive applications within a single AWS Availability Zone

99.999999999%

99.95%

1

None

None

S3 Express One Zone objects are stored in a single AWS Availability Zone that you choose.

S3 Glacier Instant Retrieval

 Long-lived, archive data accessed once a quarter with millisecond access 99.999999999%

99.9%

>= 3

90 days

128 KB

 Per-GB retrieval fees apply.

S3 Glacier Flexible Retrieval

 Long-lived archive data accessed once a year with retrieval times of minutes to hours 99.999999999%

99.99% (after you restore objects)

>= 3

90 days

NA*

 Per-GB retrieval fees apply. You must first restore archived objects before you can access them. For information, see Restoring an archived object.

S3 Glacier Deep Archive

 Long-lived archive data accessed less than once a year with retrieval times of hours 99.999999999%

99.99% (after you restore objects)

>= 3

180 days

NA**

 Per-GB retrieval fees apply. You must first restore archived objects before you can access them. For information, see Restoring an archived object.

RRS (not recommended)

Noncritical, frequently accessed data with millisecond access

99.99%

99.99%

>= 3

None

None

None

* S3 Glacier Flexible Retrieval requires 40 KB of additional metadata for each archived object. This includes 32 KB of metadata charged at the S3 Glacier Flexible Retrieval rate (required to identify and retrieve your data), and an additional 8 KB data charged at the S3 Standard rate. The S3 Standard rate is required to maintain the user-defined name and metadata for objects archived to S3 Glacier Flexible Retrieval. For more information about storage classes, see Amazon S3 storage classes.

** S3 Glacier Deep Archive requires 40 KB of additional metadata for each archived object. This includes 32 KB of metadata charged at the S3 Glacier Deep Archive rate (required to identify and retrieve your data), and an additional 8 KB data charged at the S3 Standard rate. The S3 Standard rate is required to maintain the user-defined name and metadata for objects archived to Amazon S3 Glacier Deep Archive. For more information about storage classes, see Amazon S3 storage classes.

Be aware that all of the storage classes except for S3 One Zone-IA and S3 Express One Zone are designed to be resilient to the physical loss of an Availability Zone resulting from disasters. Also, consider costs, in addition to the performance requirements of your application scenario. For storage class pricing, see Amazon S3 pricing.