The Pros

1
The Pros Cons ofContent Addressed Storage

• Arun Taneja
• Founder Consulting Analyst

2
Current Data Protection Environment

• Data Tsunami
• No Backup Windows
• Cost of Downtime Increasing
• Regulations and Compliance Requirements
• Data Protection Technology at Break Point

3
Many New Technologies to The Rescue
4
What is CAS?
5
CAS vs Networked Storage

• SAN NAS Use File Systems to Place and Locate
  Data (/abc/xyz/acme.doc)
• Hierarchical
• Difficult to Scale Beyond TBs
• Application Determines if Duplication of Object
  Exists
• Indexing can Become Complicated

6
How is CAS Done?

• Algorithm Applied to the Objects Content
• File
• Portion of a file
• Directory or file system
• Unique 128-bit Coding Results (160-bits for
  Avamar)

• Object (File, FS, Dir)

128-bit hash unique to that object (eg. MD5)
7
What Can CAS Be Used For?

• Archival Storage
• Backup and Restore
• Disaster Recovery
• Content Management

8
Issues with Existing Architectures
9
Methods for Keeping More Data Online

• Bigger Primary Storage
• Compression of Data
• Hierarchical Storage Architectures
• Data Normalization Finding Subsets of Data That
  are Common and Storing Them Only Once
• No Limit on the Effective Compression Ratio
• Indexing Systems Super Critical

10
Commonality Factoring Using CAS

• Fixed Size Atomics for Database
• Variable Size Atomics for File Systems
• CAS Algorithms Used to Calculate CA for Each
  Subset
• Data Structures Needed to Reconstruct from
  Atomics
• Above Data Kept with Atomics Data

11
CAS Example Avamar

• CAS Applied to BU/Restore, Archive and DR
  (initial focus BU/R)
• Focus on Data Reduction
• Typical Secondary to Primary Ratio is 101
• Avamar Claims 1.2 to 1
• Never Do Full Incremental Backups, Only SnapUps

12
CAS ExampleAvamar Systems Architecture

• Distributed Backup Repository
• Peer-to-Peer RAIN Architecture
• Each Node has Uniform and Consistent View of
  Repository

• Clients can Request Services from any Node
• Data Striped Across Nodes (similar to RAID)
• No Single Point of Failure
• Requires Agent on Each Client System

13
CAS Archival ExampleEMC Centera
CA of CDF Returned
Centera
Application
CDF
CA of CDF
store
CDF
XML
Calculate CA and extract metadata
C-clip
metadata
CA
store
file
Blob
API
Source EMC
14
CAS Advantages EMC Centera
15
CAS Players

• Data Center Technologies

Persist Technologies
16
CAS Futures What's Needed?

• Flexible Scaling Capabilities
• Integration with File Interfaces
• Easy API-free Application Integration
• Integrated Indexing

17
Summary
18
Taneja Group Recommendations

• Absolutely Test Out CAS Systems but
• Apply to a Project at a Time (consider the
  disruptive factor)
• Keep a Fallback Position (run systems in
  parallel)
• Test Out Recoverability Regularly
• Keep in MindMore Solutions Coming