Content Addressed Storage (CAS)

With increasing data and information, problem of storing the information is becoming a big challenge in the industries. The data which becomes old with the time, is likely to change or edited very less and said to be fixed data. But this fixed data is accessed by many users over the period of time and is going to access further. So this data cannot be deleted or removed and must be preserved for future use. The demand for managing and storing such fixed data or fixed content gave birth to Content Addressed Storage System (CAS).

Content Addressed Storage (CAS)

What is Content Addressed Storage (CAS)?

Content addressed storage or CAS is an object-based system that has been made for storing and managing fixed content data. It is designed for secure online storage and recovery of fixed content.

Unlike file-level and block-level data access that use file names and the physical location of data for storage and recovery, Content addressed storage stores user data and its information as separate objects. The stored object is assigned a globally unique address known as a content address (CA).

Example of Fixed content data is Electronics data such as contracts, claims, E-mail attachment, Digital record such as Photos, checks etc. and Rich Media such as X-Ray, CT Scan, Voice mail, radio, etc.

Need of Content Addressed Storage (CAS)?

CAS system is needed for the following below reason.

  • Storing the Fixed data which is less likely to change.
  • Managing the fixed data or content.
  • To provide security of fixed content.
  • To make fixed content available whenever needed.
  • To provide optimized and centralized managed storage solution.

CAS Architecture Diagram

Architecture Diagram of Content Addressed Storage (CAS) Image Courtesy: EMC

CAS architecture is a Redundant Array of Independent Nodes (RAIN). It contains storage nodes and access nodes networked as a cluster by using a private LAN that is internal to it.

The internal LAN can be reconfigured automatically to detect the configuration changes such as the addition of storage or access nodes. Clients access the CAS on a separate LAN, which is used for interconnecting clients and servers to the CAS.

ATA HDD are used to configure the nodes, which are low-cost and high-capacity. These nodes run an operating system with special software that implements the features and functionality required in a CAS system.

Industrial Example of CAS System

CAS EMC
Courtesy: Novell

EMC Centera is a simple, affordable, and secure repository for information archiving. EMC Centera™ is one of the good example of Content addressed storage system and its Content Addressed Storage system (CAS) is an advanced online storage infrastructure that can be used to archive files for any type of application.


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