Amazon Simple Storage Service FAQs

Find more answers in Amazon S3 Technical FAQs

General

Q: What is Amazon S3?

Amazon S3 is storage for the Internet. It’s a simple storage service that offers software developers a highly-scalable, reliable, and low-latency data storage infrastructure at very low costs.

Q: What can I do with Amazon S3?

Amazon S3 provides a simple web services interface that you can use to store and retrieve any amount of data, at any time, from anywhere on the web. Using this web service, developers can easily build applications that make use of Internet storage. Since Amazon S3 is highly scalable and you only pay for what you use, developers can start small and grow their application as they wish, with no compromise on performance or reliability. It is designed to be highly flexible: Store any type and amount of data that you want; read the same piece of data a million times or only for emergency disaster recovery; build a simple FTP application, or a sophisticated web application such as the Amazon.com retail web site. Amazon S3 frees developers to focus on innovation, not figuring out how to store their data.

Q: How can I get started using Amazon S3?

To sign up for Amazon S3, click the “Sign up for This Web Service” button on the Amazon S3 detail page. You must have an Amazon Web Services account to access this service; if you do not already have one, you will be prompted to create one when you begin the Amazon S3 sign-up process. After signing up, please refer to the Amazon S3 documentation and sample code in the Resource Center to begin using Amazon S3.

Q: What are the technical benefits of Amazon S3?

Amazon S3 was carefully engineered to meet the requirements for scalability, reliability, speed, low-cost, and simplicity that must be met for Amazon’s internal developers. Amazon S3 passes these same benefits onto any external developer. More information about the Amazon S3 design requirements is available on the Amazon S3 detail page.

Q: What can developers do now that they could not before?

Until now, a sophisticated and scalable data storage infrastructure like Amazon’s has been beyond the reach of small developers. Amazon S3 enables any developer to leverage Amazon’s own benefits of massive scale with no up-front investment or performance compromises. Developers are now free to innovate knowing that no matter how successful their businesses become, it will be inexpensive and simple to ensure their data is quickly accessible, always available, and secure.

Q: What kind of data can I store?

You can store virtually any kind of data in any format. Please refer to the Amazon Web Services Licensing Agreement for details.

Q: How much data can I store?

Individual Amazon S3 objects can range in size from 1 byte to 5 gigabytes. The number of objects you can store is unlimited.

Q: What does Amazon do with my data in Amazon S3?

Amazon will store your data and track its associated usage for billing purposes. Amazon will not otherwise access your data for any purpose outside of the Amazon S3 offering, except when required to do so by law. Please refer to the Amazon Web Services Licensing Agreement for details.

Q: Does Amazon store its own data in Amazon S3?

Yes. Developers within Amazon use Amazon S3 for a wide variety of projects. Many of these projects use Amazon S3 as their authoritative data store, and rely on it for business-critical operations.

Q: How is Amazon S3 data organized?

Amazon S3 is a simple key-based object store. When you store data, you assign a unique object key that can later be used to retrieve the data. Keys can be any string, and can be constructed to mimic hierarchical attributes.

Q: How do I interface with Amazon S3?

Amazon S3 provides simple, standards-based REST and SOAP web services interfaces that are designed to work with any Internet-development toolkit. The operations are intentionally made simple to make it easy to add new distribution protocols and functional layers.

Q: How reliable is Amazon S3?

Amazon S3 gives any developer access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of web sites. The service was designed for 99.99% availability, and carries a service level agreement providing service credits if a customer’s availability falls below 99.9%.

Q: What data consistency model does Amazon S3 employ?

Amazon S3 buckets in the US West (Northern California), EU (Ireland) and Asia Pacific (Singapore) Regions provide read-after-write consistency for PUTS of new objects and eventual consistency for overwrite PUTS and DELETES. Amazon S3 buckets in the US Standard Region provide eventual consistency.

Q: What happens if traffic from my application suddenly spikes?

Amazon S3 was designed from the ground up to handle traffic for any Internet application. Pay-as-you-go pricing and unlimited capacity ensures that your incremental costs don’t change and that your service is not interrupted. Amazon S3’s massive scale enables us to spread load evenly, so that no individual application is affected by traffic spikes.

Q: What is the BitTorrent™ protocol, and how do I use it with Amazon S3?

BitTorrent is an open source Internet distribution protocol. Amazon S3’s bandwidth rates are inexpensive, but BitTorrent allows developers to further save on bandwidth costs for a popular piece of data by letting users download from Amazon and other users simultaneously. Any publicly available data in Amazon S3 can be downloaded via the BitTorrent protocol, in addition to the default client/server delivery mechanism. Simply add the ?torrent parameter at the end of your GET request in the REST API.

Q: Are there any requirements for use of the Amazon S3 Console?

Yes, the Amazon S3 Console requires that you have a 10.x version of Adobe Flash and access to TCP port 843. These requirements do not apply to the management of other services in the AWS Management Console.

Q: Does Amazon S3 offer a Service Level Agreement (SLA)?

Yes. The Amazon S3 SLA provides for a service credit if a customer’s monthly uptime percentage is below our service commitment in any billing cycle. More information can be found here.

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Regions

Q: Where is my data stored?

Amazon S3 offers storage in the US Standard, EU (Ireland), US West (Northern California) and Asia Pacific (Singapore) Regions. You specify a Region when you create your Amazon S3 bucket. Within that Region, your objects are redundantly stored on multiple devices across multiple facilities.

Q: How do I decide which Region to store my data in?

There are several factors to consider based on your specific application. You may want to store your data in a Region that…

• ...is near to your customers, your data centers, or your other AWS resources in order to reduce data access latencies.
• ...is remote from your other operations for geographic redundancy and disaster recovery purposes.
• ...enables you to address specific legal and regulatory requirements.
• ...allows you to reduce storage costs. You can choose a lower priced Region to save money. Please see the pricing section on the S3 detail page.

Q: I’m not in the US or Europe; can I use Amazon S3?

Anyone can use Amazon S3. You just have to decide which Region you want Amazon S3 to store your data in.

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Billing

Q: How much does Amazon S3 cost?

With Amazon S3, you pay only for what you use. There is no minimum fee. You can estimate your monthly bill using the AWS Simple Monthly Calculator.

We charge less where our costs are less. Some prices vary across Amazon S3 Regions and are based on the location of your bucket. There is no Data Transfer charge for data transferred within an Amazon S3 Region via a COPY request. Data transferred via a COPY request between Regions is charged at regular rates. There is no Data Transfer charge for data transferred between Amazon EC2 and Amazon S3 within the same Region or for data transferred between the Amazon EC2 Northern Virginia Region and the Amazon S3 US Standard Region. Data transferred between Amazon EC2 and Amazon S3 across all other Regions (i.e. between the Amazon EC2 Northern California and Amazon S3 US Standard Regions) will be charged at Internet Data Transfer rates on both sides of the transfer.*

For S3 pricing information, please visit the pricing section on the S3 detail page.

* All Data Transfer In is free through October 31st 2010 (i.e. $0.00 per GB).

Q: Why do prices vary depending on which Amazon S3 Region I choose?

We charge less where our costs are less. For example, our costs are lower in the US Standard Region than in the US West (Northern California) Region.

Q: How will I be charged and billed for my use of Amazon S3?

There are no set-up fees or commitments to begin using the service. At the end of the month, your credit card will automatically be charged for that month’s usage. You can view your charges for the current billing period at any time on the Amazon Web Services web site, by logging into your Amazon Web Services account, and clicking “Account Activity” under “Your Web Services Account”.

Amazon S3 charges you for the following types of usage:

Storage Used:

In the US Standard Region, Amazon S3 storage pricing is $0.150 per GB for storage for the first 50 TB, $0.140 per GB for the next 50 TB, $0.130 per GB for the next 400 TB, $0.105 per GB for the next 500 TB, $0.080 per GB for the next 4000 TB, and $0.055 per GB for storage used over 5000 TB per month.

In the EU (Ireland) Region, Amazon S3 storage pricing is $0.150 per GB for storage for the first 50 TB, $0.140 per GB for the next 50 TB, $0.130 per GB for the next 400 TB, $0.105 per GB for the next 500 TB, $0.080 per GB for the next 4000 TB, and $0.055 per GB for storage used over 5000 TB per month.

In the US West (Northern California) Region, Amazon S3 storage pricing is $0.165 per GB for storage for the first 50 TB, $0.155 per GB for the next 50 TB, $0.145 per GB for the next 400 TB, $0.120 per GB for the next 500 TB, $0.095 per GB for the next 4000 TB, and $0.070 per GB for storage used over 5000 TB per month.

In the Asia Pacific (Singapore) Region, Amazon S3 storage pricing is $0.150 per GB for storage for the first 50 TB, $0.140 per GB for the next 50 TB, $0.130 per GB for the next 400 TB, $0.105 per GB for the next 500 TB, $0.080 per GB for the next 4000 TB, and $0.055 per GB for storage used over 5000 TB per month.

The GB of storage billed in a month is the average storage used throughout the month. This includes all object data and metadata stored in buckets that you created under your account. We measure your usage in “TimedStorage-ByteHrs,” which are added up at the end of the month to generate your monthly charges.

Storage Used Example:
You keep 2,684,354,560 bytes (or 2.5 GB) of data in your bucket for 15 days in March, and 1,342,177,280 bytes (or 1.25 GB) for 16 days.

At the end of March:
Total Byte-Hour usage = [2,684,354,560 bytes x 15 days x (24 hours / day)] + [1,342,177,280 bytes x 16 days x (24 hours / day)] = 1,481,763,717,120 Byte-Hours.

Conversion to Total GB-Months
1,481,763,717,120 Byte-Hours x (1 GB / 1,073,741,824 bytes) x (1 month / 744 hours) = 1.85 GB-Months

Total charge if stored in the US Standard Region = 1.85 GB-Months x ($0.15 / GB-Month) = $0.28.

Total charge if stored in the EU (Ireland) Region = 1.85 GB-Months x ($0.15 / GB-Month) = $0.28.

Total charge if stored in the US West (Northern California) Region = 1.85 GB-Months x ($0.165 / GB-Month) = $0.31.

Total charge if stored in the Asia Pacific (Singapore) Region = 1.85 GB-Months x ($0.15 / GB-Month) = $0.28.

Network Data Transferred:

(i) Data Transfer In: All Data Transfer In is free through October 31st 2010 (i.e. $0.00 per GB). After November 1st 2010, Data Transfer In is $0.10 per GB.

This represents the amount of data sent to Amazon S3. This charge applies whenever data is written to any of your buckets. This charge is the same for buckets in the US Standard, EU (Ireland), US West (Northern California) and Asia Pacific (Singapore) Regions.

Transfer In Example:
You upload one 500 MB file to Amazon S3 each day during a 31 day month.

Total Data Transfer In for the month = 500 MB x (1 GB / 1024 MB) x 31 days = 15.14 GB

Total Charge through October 31st 2010 = 15.14 GB x ($0.00 / GB) = $0.00

Total Charge after November 1st 2010 = 15.14 GB x ($0.10 / GB) = $1.52

(ii) Data Transfer Out: Data Transfer Out pricing for the US Standard, EU (Ireland), and US West (Northern California) Regions is free for the first GB, $0.150 per GB data transfer out up to 10 TB, $0.110 per GB for the next 40 TB, $0.090 per GB for the next 50 TB, and $0.080 for all remaining data transfer out of Amazon S3 in a month. These rate tiers take into account your aggregate Data Transfer Out usage within these regions across Amazon EC2, Amazon S3, Amazon RDS, Amazon SimpleDB, Amazon SQS, Amazon SNS and Amazon VPC.

Data Transfer Out pricing for the Asia Pacific (Singapore) Region is free for the first GB, $0.190 per GB data transfer up to 10 TB, $0.150 per GB for the next 40 TB, $0.130 per GB for the next 50 TB, and $0.120 for all remaining data transfer out of Amazon S3 in a month.

For Amazon S3, this charge applies whenever data is read from any of your buckets.

Transfer Out Example:
Assume you transfer one 500MB file out of the US Standard, EU (Ireland), or US West (Northern California) Regions each day during the month of March.

Total Data Transfer Out for the month = 500 MB x (1 GB / 1,024 MB) x 31 days = 15.14 GB

Total charge = 15.14GB x ($0.150 / GB) = $2.27

Requests:

For buckets in the US Standard, EU (Ireland) and Asia Pacific (Singapore) regions request fees are $0.01 per 1,000 PUT and LIST operations, and $0.01 per 10,000 GET operations and all other requests (except DELETE operations, which are free of charge). For US West (Northern California) buckets, request pricing is $0.011 per 1,000 PUT and LIST operations, and $0.011 per 10,000 GET operations and all other requests (except DELETE operations, which are free of charge).

Request Example:
You transfer 1,000 files into Amazon S3 and transfer 2,000 files out of Amazon S3 each day during the month of March, and delete 5,000 files on March 31st.

Total PUT requests = 1,000 requests x 31 days = 31,000 requests

Total GET requests = 2,000 requests x 31 days = 62,000 requests

Total DELETE requests = 5,000×1 day = 5,000 requests

Total charge for requests to US Standard Region = 31,000 x ($0.01 / 1,000) + 62,000 x ($0.01 / 10,000) + 5,000 x $0 = $0.310 + $0.062 = $0.38

Total charge for requests to US West (Northern California) Region buckets = 31,000 x ($0.011 / 1,000) + 62,000 x ($0.011 / 10,000) + 5,000 x $0 = $0.341 + $0.068 = $0.41

Q: How am I charged for accessing Amazon S3 through the AWS Management Console?

Normal Amazon S3 pricing applies when accessing the service through the AWS Management Console. To provide an optimized experience, the AWS Management Console may proactively execute requests. Also, some interactive operations result in more than one request to the service.

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Security

Q: How secure is my data?

Amazon S3 uses proven cryptographic methods to authenticate users. It is your choice to keep your data private, or to make it publicly accessible by third parties. If you would like extra security, there is no restriction on encrypting your data before storing it in Amazon S3.

Q: Can I comply with EU data privacy regulations using Amazon S3?

Objects stored in the EU (Ireland) Region never leave the EU unless you transfer them out. However, it is your responsibility to ensure that you comply with EU privacy laws.

Q: How can I control access to my data stored on Amazon S3?

Customers may use three mechanisms for controlling access to Amazon S3 resources: bucket policies, Access Control Lists (ACLs) and query string authentication. With bucket policies, companies can define rules which apply broadly across all requests to their Amazon S3 resources, such as granting write privileges to a subset of Amazon S3 resources. Customers can also restrict access based on an aspect of the request, such as HTTP referrer and IP address. With ACLs, customers can grant specific permissions (i.e. READ, WRITE, FULL_CONTROL) to specific users for an individual bucket or object. With query string authentication, customers can create a URL to an Amazon S3 object which is only valid for a limited time.

Q: Where can I find more information about security on AWS?

For more information on security on AWS please refer to our Amazon Web Services: Overview of Security Processes document.

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Data Protection

Q: How durable is Amazon S3?

Amazon S3 is designed to provide 99.999999999% durability of objects over a given year. This durability level corresponds to an average annual expected loss of 0.000000001% of objects. For example, if you store 10,000 objects with Amazon S3, you can on average expect to incur a loss of a single object once every 10,000,000 years. In addition, Amazon S3 is designed to sustain the concurrent loss of data in two facilities.

Q: How is Amazon S3 designed to achieve 99.999999999% durability?

Amazon S3 redundantly stores your objects on multiple devices across multiple facilities in an Amazon S3 Region. The service is designed to sustain concurrent device failures by quickly detecting and repairing any lost redundancy. When processing a request to store data, the service will redundantly store your object across multiple facilities before returning SUCCESS. Amazon S3 also regularly verifies the integrity of your data using checksums.

Q: What checksums does Amazon S3 employ to detect data corruption?

Amazon S3 uses a combination of Content-MD5 checksums and cyclic redundancy checks (CRCs) to detect data corruption. Amazon S3 performs these checksums on data at rest and repairs any corruption using redundant data. In addition, the service calculates checksums on all network traffic to detect corruption of data packets when storing or retrieving data.

Q: What is Versioning?

Versioning allows you to preserve, retrieve, and restore every version of every object stored in an Amazon S3 bucket. Once you enable Versioning for a bucket, Amazon S3 preserves existing objects anytime you perform a PUT, POST, COPY, or DELETE operation on them. By default, GET requests will retrieve the most recently written version. Older versions of an overwritten or deleted object can be retrieved by specifying a version in the request.

Q: Why should I use Versioning?

Amazon S3 provides customers with a highly durable storage infrastructure. Versioning offers an additional level of protection by providing a means of recovery when customers accidentally overwrite or delete objects. This allows you to easily recover from unintended user actions and application failures. You can also use Versioning for data retention and archiving.

Q: How do I start using Versioning?

You can start using Versioning by enabling a setting on your Amazon S3 bucket. For more information on how to enable Versioning, please refer to the Amazon S3 Technical Documentation.

Q: How does Versioning protect me from accidental deletion of my objects?

When a user performs a DELETE operation on an object, subsequent default requests will no longer retrieve the object. However, all versions of that object will continue to be preserved in your Amazon S3 bucket and can be retrieved or restored. Only the owner of an Amazon S3 bucket can permanently delete a version.

Q: How can I ensure maximum protection of my preserved versions?

Versioning’s MFA Delete capability, which uses multi-factor authentication, can be used to provide an additional layer of security. By default, all requests to your Amazon S3 bucket require your AWS account credentials. If you enable Versioning with MFA Delete on your Amazon S3 bucket, two forms of authentication are required to permanently delete a version of an object: your AWS account credentials and a valid six-digit code and serial number from an authentication device in your physical possession. To learn more about enabling Versioning with MFA Delete, including how to purchase and active an authentication device, please refer to the Amazon S3 Technical Documentation.

Q: How am I charged for using Versioning?

Normal Amazon S3 rates apply for every version of an object stored or requested. For example, let’s look at the following scenario to illustrate storage costs when utilizing Versioning (let’s assume the current month is 31 days long):

1) Day 1 of the month: You perform a PUT of 1,073,741,824 bytes (or 1 GB) on your bucket.

2) Day 15 of the month: You perform a PUT of 524,288,000 bytes (or 500 MB) within the same bucket using the same key as the original PUT on Day 1.

When analyzing the storage costs of the above operations, please note that the 1 GB object from Day 1 is not deleted from the bucket when the 500 MB object is written on Day 15. Instead, the 1 GB object is preserved as an older version and the 500 MB object becomes the most recently written version of the object within your bucket. At the end of the month:

Total Byte-Hour usage - [1,073,741,824 bytes x 31 days x (24 hours / day)] + [524,288,000 bytes x 16 days x (24 hours / day)] = 1,000,190,509,056 Byte-Hours.

Conversion to Total GB-Months - 1,000,190,509,056 Byte-Hours x (1 GB / 1,073,741,824 bytes) x (1 month / 744 hours) = 1.25 GB-Months

Total charge if stored in the US Region = 1.25 GB-Months x ($0.150 / GB-Month) = $0.19.

Total charge if stored in EU (Ireland) Region = 1.25 GB-Months x ($0.150 / GB-Month) = $0.19.

Total charge if stored in the US West (Northern California) Region = 1.25 GB-Months x ($0.165 / GB-Month) = $0.21.

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Reduced Redundancy Storage (RRS)

Q: What is RRS?

Reduced Redundancy Storage (RRS) is a new storage option within Amazon S3 that enables customers to reduce their costs by storing non-critical, reproducible data at lower levels of redundancy than Amazon S3’s standard storage. RRS provides a lower cost, less durable, highly available storage option that is designed to sustain the loss of data in a single facility.

Q: Why would I choose to use RRS?

RRS is ideal for non-critical or reproducible data. For example, RRS is a cost-effective solution for sharing media content that is durably stored elsewhere. RRS also makes sense if you are storing thumbnails and other resized images that can be easily reproduced from an original image.

Q: What is the durability of Amazon S3 when using RRS?

RRS 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 (i.e. 0.01% of 10,000 objects). This annual loss represents an expected average and does not guarantee the loss of 0.01% of objects in a given year.

The RRS option stores objects on multiple devices across multiple facilities, providing 400 times the durability of a typical disk drive, but does not replicate objects as many times as standard Amazon S3 storage, and thus is even more cost effective. In addition, RRS is designed to sustain the loss of data in a single facility.

Q: How do I know if I lose an RRS object?

If an RRS object 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 (RRS) object loss. Customers can configure their bucket so that when Amazon S3 detects the loss of an RRS object, a notification will be sent through Amazon Simple Notification Service (SNS). This enables customers to replace lost RRS objects.

Q: How do I specify that I want to store my data using RRS?

All objects in Amazon S3 have a storage class setting. The default setting is STANDARD. You can use an optional header on a PUT request to specify the setting REDUCED_REDUNDANCY.

Q: Are my RRS objects backed with the Amazon S3 Service Level Agreement?

Yes, you can utilize RRS without sacrificing the availability of your data. RRS is backed with the Amazon S3 Service Level Agreement, providing financial penalties if availability is less than 99.9% in a given month.

Q: How will my performance be impacted as a result of using RRS?

You should expect the same latency and throughput as standard Amazon S3 storage when using RRS.

Q: How am I charged for using RRS?

Storage pricing for RRS can be found on the pricing section of the Amazon S3 detail page. Standard Amazon S3 rates apply for bandwidth and requests.