Administrator’s Command Line Guide

Chapter 3. Accessing Storage Clusters via S3 Protocol
3.1.3 Object Storage Components
This section offers more detail on S3 storage components: gateways, object servers, and name servers; and
describes S3 management tools and service buckets.
3.1.3.1 Gateway
A gateway performs the following functions:
• Receives S3 requests from the web server (via NGINX and FastCGI).
• Parses S3 packets and validates S3 requests (checks fields of a request and XML documents in its body).
• Authenticates S3 users.
• Validates access permissions to buckets and objects using ACL.
• Collects statistics on the number of various requests as well as the amount of the data received and
transmitted.
• Determines paths to NS and OS storing the object’s data.
• Inquires names and associated metadata from NS.
• Receives links to objects stored on OSes by requesting the name from NSes.
• Caches metadata and ACL of S3 objects received from NSes as well as the data necessary for user
authentication also stored on the NSes.
• Acts as a proxy server when clients write and read object data to and from the OSes. Only the
requested data is transferred during read and write operations. For example, if a user requests to read
10MB from a 1TB object, only said 10MB will be read from the OS.
S3 gateway consists of incoming requests parser, type-dependent asynchronous handlers of these requests,
and an asynchronous handler of the interrupted requests that require completion (complex operations such
as bucket creation or removal). Gateway does not store its state data in the long-term memory. Instead, it
stores all the data needed for S3 storage in the object storage itself (on NS and OS).
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