Object Storage Service:What is OSS

Learn about OSS

• Video

  Watch the following video to get a quick overview of OSS.

• FAQ

  See the OSS FAQ for answers to common questions.

How OSS works

Data is stored as objects in buckets. To store data in OSS, you must first create a bucket and specify its properties, such as its region, access permissions, and storage class. After creating the bucket, you can upload data as objects and assign a unique object key to each object.

When you send a request, OSS verifies the sender's identity using symmetric encryption with an AccessKey ID and AccessKey Secret.

Object operations in OSS are atomic and provide strong consistency.

• Bucket

  A bucket is a container used to store objects. All objects must belong to a bucket. A bucket has various configuration properties, including its region, access permissions, and storage class. You can create different types of buckets to store different data based on your needs.

• Object

  An object, also known as a file, is the basic data unit in OSS. Unlike traditional file systems, objects do not have a hierarchical folder structure. An object consists of metadata (Object Meta), user data (Data), and a key (filename). An object is uniquely identified by its key within a bucket. Object metadata is a set of key-value pairs that describe object properties, such as file type and encoding. You can also store custom information in the metadata.

• Object key

  In SDKs for various languages, ObjectKey, Key, and ObjectName are synonymous. They all refer to the name of an object that you specify for an operation. For example, when you upload an object to a bucket, the ObjectKey is the full name of the object, which includes the full path and file extension, such as abc/efg/123.jpg.

• Region

  A region is the physical location of an OSS data center. You can choose a region to create a bucket based on factors such as cost and the source of your requests. A region that is geographically closer to your users generally provides faster access. For more information, see Regions supported by OSS.

• Endpoint

  An endpoint is the domain name used to access OSS. OSS provides services through HTTP RESTful APIs. You must use different endpoints to access OSS in different regions. The endpoints for accessing the same region over the internet and an internal network are also different. For example, the internet endpoint for the China (Hangzhou) region is oss-cn-hangzhou.aliyuncs.com, and the internal network endpoint is oss-cn-hangzhou-internal.aliyuncs.com. For more information, see Endpoints for each region.

• AccessKey

  An AccessKey pair, also known as an AK, consists of an AccessKey ID and an AccessKey secret used for identity verification. OSS uses the AccessKey ID and AccessKey secret for symmetric encryption to verify the identity of a request sender. The AccessKey ID identifies the user. The AccessKey secret is a key that you use to encrypt signature strings, which OSS then uses to verify the signature. You must keep your AccessKey secret confidential. For OSS, an AccessKey pair can be obtained from one of the following sources:

  • An AccessKey pair that belongs to the bucket owner.

  • An AccessKey pair granted to a third party by the bucket owner through RAM authorization.

  • An AccessKey pair granted to a third party by the bucket owner through Security Token Service (STS).

  For more information about AccessKey pairs, see Create an AccessKey pair.

• Atomicity and strong consistency

  Object operations in OSS are atomic. An operation either succeeds or fails. An object does not have an intermediate state. When an object is uploaded, OSS ensures that the object you read is complete. OSS does not return a partially uploaded object.

  Object operations in OSS provide strong consistency. When you receive a successful response for an upload (PUT) operation, the uploaded object is immediately available for read operations, and its redundant data has been successfully written. An upload does not have an intermediate state. This means you can immediately read data after a write operation. For a delete operation, after you successfully delete a specified object, it immediately ceases to exist.

For a complete overview of basic OSS concepts, see Basic concepts.

Key features

• Versioning

  Versioning is a bucket-level data protection feature. When you enable versioning, overwrite and delete operations create historical versions of an object instead of permanently removing data. If you accidentally overwrite or delete an object, you can restore it to any of its previous versions. For more information, see Versioning.

• Bucket policy

  A bucket owner can use a bucket policy to grant different users specific permissions to access designated OSS resources. For example, you can grant cross-account or anonymous access to manage an entire bucket or specific resources within it. You can also grant different permissions (such as read-only, read/write, or full control) to different RAM users under the same account. For information about how to configure a bucket policy, see Use bucket policies to grant permissions to access OSS.

• Cross-region replication

  Cross-region replication is the automatic and asynchronous (near real-time) replication of objects across buckets in different OSS data centers (regions). It replicates object creation, updates, and deletions from a source bucket to a destination bucket in a different region. This feature supports use cases such as cross-region disaster recovery and data replication. For more information, see Cross-region replication.

• Data encryption

  Server-side encryption: When you upload an object, OSS encrypts it upon receipt and stores the encrypted data. When you download the object, OSS automatically decrypts it before sending it to you. The HTTP response header indicates that the object was encrypted on the server side. For more information, see Server-side encryption.

  Client-side encryption: You encrypt your data locally before uploading it to OSS. For more information, see Client-side encryption.

• Permanent data retention

  By default, data uploaded to a bucket is stored permanently, except in the following cases:

  • Data is manually deleted using the OSS console, an API or SDK, ossutil, or ossbrowser. For more information, see Delete objects.

  • Data is automatically deleted after a specified period based on a lifecycle rule. For more information, see Lifecycle rules based on last modified time.

  • Your data is deleted if you fail to clear an overdue payment within 15 days after your OSS service is suspended. For more information, see Service suspension due to overdue payments.

For a complete overview of OSS features, see Features.

Ways to use OSS

OSS provides flexible methods for uploading, downloading, and managing data.

• Use the console

  OSS provides a web-based console where you can manage your OSS resources. For more information, see OSS console and OSS console overview.

• Use an API or SDK

  OSS provides RESTful APIs and SDKs for various programming languages to facilitate custom development. For more information, see OSS API Reference and OSS SDK Reference.

• Use tools

  OSS provides various management tools, including the graphical tool ossbrowser, the command-line tool ossutil, and the FTP tool ossftp. For more information, see Common OSS tools.

• Use Cloud Storage Gateway

  Buckets in OSS have a flat structure and do not have concepts like file system directories. If you want to use OSS like a local folder or disk, you can do so by configuring Cloud Storage Gateway. For more information, see the Cloud Storage Gateway product details page.

Billing

OSS supports three billing methods:

• Pay-as-you-go — the default method. Charges are based on actual usage and billed after consumption. Best for workloads with unpredictable usage. For details, see Pay-as-you-go.

• Subscription (resource plans) — pre-purchase resource plans at discounted rates to offset fees for specific billable items. Best for workloads with predictable usage. For details, see Resource plans.

• Storage capacity units (SCUs) — use SCUs to offset storage fees across OSS and other Alibaba Cloud storage services. For details, see SCU (Storage Capacity Unit).

Resource plans and SCUs are more cost-effective than pay-as-you-go for consistent usage. If usage exceeds your plan or SCU quota, the excess is billed at pay-as-you-go rates. Size your plans based on expected workloads.

Related services

After you store data in OSS, you can use other Alibaba Cloud products and services to process it.

The following Alibaba Cloud products and services are commonly used with OSS:

• Image Processing (IMG): Perform operations such as format conversion, scaling, cropping, rotating, and watermarking on images stored in OSS. For more information, see Quick start for Image Processing.

• Elastic Compute Service (ECS): Provides simple, efficient, and elastically scalable cloud computing services. For more information, see the ECS product details page.

• Content Delivery Network (CDN): Caches OSS resources on edge nodes across different regions to accelerate downloads of frequently accessed files. For more information, see the CDN product details page.

• E-MapReduce: A big data processing solution that is built on ECS and based on open source frameworks like Apache Hadoop and Apache Spark. It allows you to easily analyze and process your data. For more information, see the E-MapReduce product details page.

• Online Migration Service: You can use the Online Migration Service to easily migrate data from third-party sources, such as Amazon S3 or Google Cloud Storage, to OSS. For more information, see the Online Migration Service tutorial.

• Offline migration service: If you need to upload terabytes or petabytes of data to OSS but have limited network bandwidth, you can use the Lightning Cube offline data migration service. For more information, see Offline migration (Lightning Cube).

Other Alibaba Cloud storage services

In addition to object storage, Alibaba Cloud provides other types of storage services, such as file storage and block storage, to meet your business needs in different scenarios. For more information, see Introduction to Alibaba Cloud storage services.

For customer stories and solutions related to Alibaba Cloud storage services, see Alibaba Cloud Storage Family.