During this presentation Stefan Piesche, Chief Technology Officer at Constant Contact, will discuss how he and his team were able to grow and scale Constant Contact’s technology infrastructure by aligning technology with horizontal business growth to improve performance and reduce costs. He will share some of the lessons learned, best practices, and recommendations for other technology executives looking to transform their technology infrastructure to business.

1. Transforming Constant Contact with
DataStax Enterprise
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2. Stefan Piesche, Chief Technology Officer
© Copyright 2013 Constant Contact Inc. 2
BIO
§ Stefan focuses on evaluating new
technologies to determine how they can
help expand the Company's products and
service architecture to accommodate future
growth and increased performance.
§ To do this, he combines technology vision
with practical delivery capabilities and
engineering best practices.
§ In previous roles at Cobalt Group and
Trilogy Enterprises, Stefan has developed
and driven corporate technology strategy
and provided technical direction, design
and architecture for all product
development.
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3. Constant Contact
• 500,000+ Small Businesses
• 70% ≤ 10 employees
• 1:1 interactions x 10,000/day
© Copyright 2013 Constant Contact Inc. 3#Cassandra13

4. Constant Contact - Engineering
• ~200 Developers, QA and Operations
• ca. 2500 servers
• 2.5 PB storage managed
• Java
• Ruby & Rails (96 node JRuby cluster)
• DB2, MySQL, Cassandra
© Copyright 2013 Constant Contact Inc. 4#Cassandra13

5. Goals for Constant Contact SAAS
Become a Multi Product Company
Growth via Horizontal Product Expansion: Go from
1 to Many
Expand the Organization (more Dev teams)
Grow via Mergers & Acquisitions
© Copyright 2013 Constant Contact Inc. 5#Cassandra13

6. Tech in 2009
© Copyright 2013 Constant Contact Inc. 6
• Monolithic
• DB Centric
• Narrow Tech Stack:
Websphere & DB2
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7. Pros and Cons
+ Perfectly Suited for a Single Product,
Vertically Growing Company
+ Easy to Understand for Dev Teams
- No Horizontal Scale
- Velocity
- Long Builds
- Many SPOFs
© Copyright 2013 Constant Contact Inc. 7#Cassandra13

8. Technology Strategy Goals 2010 – 2015
Multi Datacenter (Active-DR to active-passive to active-active)
Horizontal Scale
Extensibility
Cost Effective & Predictable ($$ per 1000 customers)
Improve Dev Velocity
Fault Tolerant
© Copyright 2013 Constant Contact Inc. 8#Cassandra13

9. Tech Strategy Approach
SOA Open source
DB2
replacement:
MySQL & ?
Integrate
Rails
Sharding? CI/CD
TDD
Websphere -
> JBoss
© Copyright 2013 Constant Contact Inc. 9#Cassandra13

10. Sharding Pros and Cons
+ Semi-Predictable Scale
- Difficult to Introduce in a Monolithic
Architecture (apps think data is in one place)
- Hard to Manage (Operations)
- Not always Cost Effective
© Copyright 2013 Constant Contact Inc. 10#Cassandra13

11. Many of our Large Scale Data Needs are
Non-Relational
Content
Tracking Events (opens, clicks, FB posts, tweets,
event registrations)
© Copyright 2013 Constant Contact Inc. 11
Cassandra to the Rescue
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12. Why Cassandra?
High Performance
‘Transparent’ Sharding
Horizontally Scalable
Fault Tolerant
Multi DC Support
Cost Effective
Replaced DB2 and SAN for >$1MM per DC with 72 node cluster
supporting 2 DC for $250k
© Copyright 2013 Constant Contact Inc. 12#Cassandra13

13. Cassandra Clusters at Constant Contact
Data
1BN Pieces
of Content
Managed
100BN
Events
Tracked
100-150BN
Records
Analyzed
© Copyright 2013 Constant Contact Inc. 13#Cassandra13

14. Cassandra Clusters at Constant Contact
© Copyright 2013 Constant Contact Inc. 14
Data
1 - 72 Node
Cluster with 36 TB
usable for
Content
1 - 72 Node
Cluster with 36 TB
usable for
Tracking (will
expand to 200
nodes over time)
1 - 24 Node
Cluster with 60 TB
usable for
Analytics (will
expand to 150 TB
usable over time)
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15. Clusters at CTCT
© Copyright 2013 Constant Contact Inc. 15
36 Nodes
Event tracking
36 Nodes
Event tracking Analytics
24 Nodes
36 Nodes
Content
36 Nodes
Content
Santa Clara Boston
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16. Results
Reduced
Cost by 80%
+
Higher FT –
No Outages
Yet J
5-10x
Performance
Enables Use
Cases We
Couldn't Do
Before.
• Event tracking -
used to be 90
days
© Copyright 2013 Constant Contact Inc. 16#Cassandra13

17. Learnings
Living on the Bleeding Edge can Pay Off (we
started with version 0.7)
Start Small
Fortune Favors the Bold, but the Prepared:
Partner with Vendors
Migration Process: Dual Writes, then Dual
Reads, then Primary Reads from Cassandra,
Finally Deprecating the old RDBMS
© Copyright 2013 Constant Contact Inc. 17#Cassandra13

18. © Copyright 2013 Constant Contact Inc. 18#Cassandra13