Get On Demand Education Anytime, Anywhere

with Coursera and DataStax

Daniel Chia

@DanielJHChia

Software Engineer, Infrastructure

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Webinar Housekeeping

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1 About Coursera

2 Requirements for a modern database platform

3 MySQL: The challenges and why we migrated

4 Cassandra versus MongoDB and HBase

5 Why Apache Cassandra and DataStax

6 Finding success with DataStax Enterprise

4

Today’s Agenda

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100+ Partners

> 1000 Courses

11 Million learners

A Peek into Coursera

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• Video courses

• Announcements for videos and assignments

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A Peek into Coursera

Your Final Project

This is your chance to apply the course concepts to real-world situations

• In-video quizzes

• Assignment and evaluation

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A Peek into Coursera

• Web, Android + iOS

• Identify verified certificate

Dropping Courses to On-Demand

• The most common complaint we hear from learners is that

courses run infrequently and are not accessible.

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….so we created On-Demand.

55%of learners cite missing a

deadline as the reason for

dropping a course

Application Availability Matters

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• A global reach of learners – 11

Million worldwide

• Application downtime leads to poor

customer experience

• Especially relevant to in-video

quizzes & assessment

Requirements for A Modern Database Platform

• 99.99% application availability guarantees always-on learning

experiences

• Reliable performance at massive scale for over 11 million users

• Ease of use operationally

• Application performance with low latency

• Multi-region writes replication

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Technical Environment @Coursera

• 100% hosted on AWS

• Service-oriented architecture

• Mix of MySQL and DataStax for persistence

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• Normalized SQL data model causes

very expensive queries

• Limitations in innovation of new

features due to scale concerns

• MySQL’s single points of failure

causes unexpected application

downtime

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Challenges with MySQL

Scalability Limits and Rigidity with MySQL

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Uh-oh…

Doesn’t fit in existing sharding

Limited Scalability with MySQL

• Scale up

• Scale out (sharding)

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• Columnar model

• Tunable consistency

• Multi-data center replication

• Thriving Open Source community with

enterprise support

• Easier setup

C*.

Cassandra vs. MongoDB & HBase

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Cassandra vs. MongoDB• Used to run it as KV store, but

supports document model

• Master would sometimes lock up,

but not failover

• Has indexing

Cassandra vs. HBase• Many things to set up

• Only runs in one AZ out of the box

on AWS

• Consistent model

• Multi-region replication with

Cassandra

DataStax Enterprise Platform Overview

In-Memory

In-memory database option allows data to be stored on RAM

instead of on disk. Delivers fast response times on frequently

accessed data for transactional applications.

Search

Built-in enterprise search feature on Cassandra

data via Solr. Allows you to search vast volumes of

data quickly to deliver optimal performance.

Analytics

Streaming data, real-time and batch analytics on

Cassandra data with external Hadoop integration. Helps

consume and analyze customer data to deliver the most

personalized experience.

Expert Support

24x7 support plus software maintenance, bug fixes,

and performance reviews. Emergency bug fixes and

support gives customers the peace of mind that their

mission critical applications are always online.

Visual Admin

DataStax OpsCenter is a visual, browser based interface for

managing Cassandra and DataStax clusters. Visual

management for administration, performance monitoring

supplies greater ease of use and reduces TCO.

Management Services

Automatic services transparently handle maintenance and

performance tuning. Enables IT departments to easily

manage health of the database reducing operational

expenditure.

Cassandra Certified

DataStax production certifies Apache Cassandra. Gives customers

the commercial confidence that Cassandra has been through a

rigorous testing process at massive scale along with additional

enterprise functionality.

Security

Comprehensive enterprise security feature set including

encryption, audit logging, authentication and LDAP/Active

Directory integration. Protects customer data against

unauthorized access and meet regulatory and compliance

requirements.

Performance Metrics

• Read latency: 1ms, 5ms, 20ms (median, p95, p99)

• Write latency: 1ms, 2ms, 3ms (median, p95, p99)

• Many rolling restarts without application downtime

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DataStax ≠ [database XYZ]

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- Albert Einstein

“But if you judge a fish by its ability to climb a tree, it

will live its whole life believing that it is stupid.”

Migration from MySQL to DataStax Enterprise

• Transition needs time, carries some risk

– Pick one feature first

• Mindset shift & expertise

• Data modeling consulting

• Libraries / Patterns / Data-as-a-Service

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From SQL to CQL - Mindset Shift

• Everyone knows SQL

• Not everyone knows Cassandra / NoSQL

• Need to know queries beforehand

• Our experience with CQL

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Thank you!

Input questions at any time

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