C* Summit 2013: Aligning Technology Infrastructure With Horizontal Business Growth by Stefan Piesche

Transforming Constant Contact with DataStax Enterprise

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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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Constant Contact

•  500,000+ Small Businesses •  70% ≤ 10 employees •  1:1 interactions x 10,000/day

© Copyright 2013 Constant Contact Inc. 3 #Cassandra13

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


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


Tech in 2009


• Monolithic

• DB Centric

• Narrow Tech Stack: Websphere & DB2

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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


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


Tech Strategy Approach

SOA Open source DB2

replacement: MySQL & ?

Integrate Rails Sharding? CI/CD

TDD Websphere -> JBoss


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


Many of our Large Scale Data Needs are Non-Relational

Content

Tracking Events (opens, clicks, FB posts, tweets, event registrations)


Cassandra to the Rescue

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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


Cassandra Clusters at Constant Contact

Data

1BN Pieces of Content Managed

100BN Events Tracked

100-150BN Records Analyzed


Cassandra Clusters at Constant Contact


Data

1 - 72 Node Cluster with 36 TB

usable for Content


usable for Tracking (will expand to 200

nodes over time)


usable for Analytics (will

expand to 150 TB usable over time)

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Clusters at CTCT


36 Nodes

Event tracking36 Nodes

Event tracking Analytics24 Nodes

36 Nodes

Content36 Nodes

Content

Santa Clara Boston

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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


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

