Content Addressed Storage

1. Section 2 : Storage Networking Technologies and Virtualization Content Addressed Storage Chapter 9

2. Lecture 19 • Content Addressed Storage (CAS): features and Benefits of a CAS

3. Chapter Objectives Upon completion of this chapter, you will be able to: • Describe CAS, fixed content and archives, traditional storage solutions for archive • Describe the features and benefits of a CAS based storage strategy • List the physical and logical elements of CAS • Describe the storage and retrieval process for CAS data objects • Describe the best suited operational environments for CAS solutions

4. Lesson: CAS Overview Upon completion of this lesson, you be able to: • Define fixed content • Describe traditional archival solutions and its shortcoming • Define Content Addressed Storage (CAS) • List benefits of CAS

5. What are Fixed Content and Archives Generate New Revenues Improve Service Levels Leverage Historical Value Digital Assets Retained For Active Reference And Value Electronic Documents • Contracts, claims, etc. • E-mail and attachments • Financial spread sheets • CAD/CAM designs • Presentations Digital Records • Documents • Checks, securities trades • Historical preservation • Photographs • Personal / professional • Surveys • Seismic, astronomic,geographic Rich Media • Medical • X-rays, MRIs, CTI • Video • News / media, movies • Security surveillance • Audio • Voicemail • Radio

6. Challenges of Storing Fixed Content • Fixed content is growing at more than 90% annually • Significant amount of newly created information falls into this category • New regulations require retention and data protection • Often, long-term preservation is required (years-decades) • Simultaneous multi-user online access is preferable to offline storage • Need faster access to fixed content • Need for location independent data, enabling technology refresh and migration • Traditional storage methods are inadequate

7. Traditional storage solutions for Archive • Three categories of archival solution are: • Online, nearline, and offline based on the means of access • Traditional archival solution were offline • Traditional archival process used optical disks and tapes as media for archival • An archive is often stored on a Write Once Read Many (WORM) device, such as a CD-ROM

8. Shortcomings of Traditional Archiving Solutions • Tape is slow, and standards are always changing • Optical is expensive, and requires vast amounts of media • Recovering files from tape and optical is often time consuming • Data on tape and optical is subject to media degradation • Both solution require sophisticated media management CAS has emerged as an alternative to traditional archiving solutions

9. What is Content Addressed Storage (CAS) • Object-oriented, location-independent approach to data storage • Repository for the “Objects” • Access mechanism to interface with repository • Globally unique identifiers provide access to objects

10. Benefits of CAS Additional Task Research on role of CAS in ILM Strategy • Content authenticity • Content integrity • Location independence • Single-instance storage (SiS) • Retention enforcement • Record-level protection and disposition • Technology independence • Fast record retrieval

11. Lesson Summary Key points covered in this lesson: • CAS Definition • Challenges of Storing Fixed Content • Shortcomings of Traditional Archiving Solutions • Benefits of CAS

12. Lecture 20 • CAS Architecture, Storage and Retrieval, Examples.

13. Lesson: CAS Architecture Upon completion of this lesson, you will be able to: • Describe CAS architecture • Describe Physical and logical elements of CAS • Describe data storage and retrieval process in CAS environment • CAS examples

14. API Physical Elements of CAS • Storage devices (CAS Based) • Storage node • Access node • Servers (to which storage devices get connected) • Client Storage Nodes Private LAN Access Nodes IP CAS System Server

15. API CAS Terminology • Application Programming Interface (API) • A set of function calls that enables communication between applications or between an application and an operating system • BLOB (Binary Large Object) • The actual data without the descriptive information (metadata) • The Distinct Bit Sequence (DBS) of user data represents the actual content of a file and is independent of the filename and physical location

16. CAS Terminology (Cont) • C-Clip • A package containing the user's data and associated metadata • C-Clip ID (C-Clip handle or C-Clip reference) is the CA that the system returns to the client application • Content Address (CA) • An identifier that uniquely addresses the content of a file and not its location. Unlike location-based addresses, content addresses are inherently stable and, once calculated, they never change and always refer to the same content • C-Clip Descriptor File (CDF) • The additional XML file that the system creates when making a C-Clip. This file includes the content addresses for all referenced BLOBs and associated metadata

17. Client presents data to API to be archived Unique Content Address is calculated Object is sent to CAS System via CAS API over IP API How CAS Stores a Data Object CAS System Application Server Client C-Clip (Object) CDF

18. Client presents data to API to be archived Unique Content Address is calculated Object is sent to CAS System via CAS API over IP API Acknowledgement returned to application CAS System validates the Content Address and stores the object Clip ID is retained and stored for future use How CAS Stores a Data Object CAS System Application Server Object Client

19. 4 2 3 Retrieval request issent to the CAS System viaCAS API over IP Application findsContent Address ofobject to be retrieved CAS authenticatesthe request anddelivers the object 1 Object is needed byan application API C-Clip ID How CAS Retrieves a Data Object CAS System Application Server Client

20. CAS Features • Features available with most CAS systems are: • Integrity checking • Data protection • Local replication • Remote replication • Load balancing • Scalability • Self-diagnosis and repair • Report generation and event notification • Fault tolerance • Through the use of redundant components and data protection schemes • Audit trails • Documentation of management activities, access and disposition of data

21. API Application Server Example 1: CAS Healthcare Solution Hospital • Each X-ray image ranges from about 15MB to over 1GB • Patient record is stored online for a period of 60-90 days • Beyond 90 days patient records are archived Stored locally for Data Stored Short-Term Use on CAS Patient Studies (60 Days) CAS System

22. API Application Server Example 2: CAS Financial Solution Bank • Check image size is about 25KB • Check imaging service provider may process 50–90 million check images per month • Checks are stored online for a period of 60 days • Beyond 60 days data is archived CAS System

23. Lesson Summary Key points covered in this lesson: • CAS architecture • Physical and logical elements of CAS • CAS storage and retrieval process • CAS solution examples

24. Chapter Summary Key points covered in this chapter: • Benefits of CAS based storage strategy • Overview of physical and logical elements of CAS • Storing and retrieving data from CAS • CAS application examples