Welcome to this section on What is OSS? Before we talk about what OSS is, let's first have a brief overview of two main types of traditional storage available in Alibaba Cloud. These are file storage and block storage. File storage, also known as networked storage is based on a shared file system. This type of storage gives multiple clients the ability to access the same shared data across a network. The interface for this is generally on the client side. The two most popular protocols for access in this type of storage is NFS and SMB.

The second type of storage is block Storage. Block storage is a high performance, low latency block storage service for Alibaba Cloud ECS virtual machines. And it supports random or sequential read and write operations. Block storage is similar to a physical disc. You can format a block storage device and create a file system on it to meet the data storage needs of your business. File and block storage services are structured data services and are priced based on the end user defined in the capacity required. In other words, you pay for what you provision.

So what is OSS? The Object Storage Service or OSS is a service that enables you to store, back up and archive any amount of non-structured data such as images, videos, documents in the cloud. Unlike a structured file service, where you would navigate to a file through its directory structure, files in OSS are uploaded into a container and each file has its own unique address to access it.

OSS is a cost effective, highly secure, easily scalable and highly reliable cloud storage solution. Using OSS, you can store and retrieve any type of data at any time and from anywhere. You can use API operations and SDKs provided by Alibaba cloud or OSS migration tools to transfer massive amounts of data into or out of Alibaba Cloud's OSS.

So what are the advantages over using traditional storage services? The first one is reliability. OSS offers up to 99.995% service availability to protect against service outages and up to 12 nines of data durability to keep your data safe. It offers automatic scaling without effecting external services. It also offers automatic redundant data backup. And with the optional cross-region replication, it can support automatic failover. So redundancy.

There are two types of redundancy available in OSS. Local redundant storage, known as LRS and zone redundant storage known as ZRS. LRS stores the data of each object on multiple devices in the same region which ensures data durability and availability in case hardware failure. ZRS distributes user data across three zones within the same region. Even if one zone becomes unavailable, your data will still be accessible. The integrity of data is periodically checked to discover data damage caused by factors such as hardware failure. OSS reconstructs and repairs damaged data by using redundant data.

Security. OSS provides enterprise grade multilevel security and denial of service attack protection. It supports multi-user resource isolation and remote disaster recovery. It also provides authentication authorization, IP address, blacklist and whitelist support and Resource Access Management or RAM account features. And provides comprehensive logging to help trace malicious access.

Costs. OSS charges fees based on actual usage. The fees incurred within an hour are billed in the next hour. Fees are calculated based on the formula fees equals actual usage times unit price. And the term actual usage is based on the volume of storage used, the amount of data transferred and the number of API requests made. There are no upfront costs and uploading data into OSS is free of charge. It's easy to use.

OSS provides a standard restful API interface, a wide range of SDK client tools and a web based console. You can easily upload, download, retrieve, and manage massive amounts of data for websites and applications in the same way as for regular files in windows. There is no limit on the number of files. File sizes can be from one bite to a maximum size of 48.8 terabytes for a single file. The maximum size however, is dependent on the method use to upload. And unlike traditional hardware storage, OSS enables you to easily scale up or expand your storage space as needed.

It supports streaming upload and download which is suitable for business scenarios. For example, where you need to simultaneously read and write videos and other large files. And it offers lifecycle management. You can delete expired by data in batches or transition the data to lower cost archive services. Some of the other advantages include image processing, which supports format conversion, thumbnails, cropping, watermarks, scaling and other operations. Audio video transcoding, which provides high quality, high speed, parallel audio/video transcoding capabilities for audio/video files stored in OSS. And Alibaba's content delivery network can be used to speed up the delivery of content stored in OSS.

That concludes the section on what is OSS? In the next section, we will cover OSS concepts.