Recently myself and my colleague - Saneesh - did a presentation to some of our peers and colleagues on the upcoming trend of this new distributed storage for web applications. Thought of sharing it with the rest of you

1. What is NoSQL ?
 Distributed storage. Varieties of ways to access / store data.
 Varieties of open source offerings
 Mostly clones based on either Amazon Dynamo, Google
BigTable, DHT
 Designed to deliver massive scalability
 Facebook, Twitter, Digg, Yahoo, LinkedIn, Google, Bing, Baidu,
Rackspace, Nokia depend on NoSQL
 Not for every one !
 Lacks transaction, atomic consistency
 Yes, we will still need RDBMS around for some more time

2. How did we get here ?
 How do I scale my application to handle millions of customers ?
 Do I really need data normalization or transaction support for my
application ?
 Simplicity to manage within the cloud
 Do I need immediate or eventual realization ?
 Prefer schema less for my application
 Want to simply store documents, JSON object, better ORM
 Need for high availability and performance than complex data
warehousing/mining support
 Now that I have my apps on cloud, how do I simplify my db
administration ?
 Dynamic Node management
 Challenges in normalizing data with sharding , optimistic locking
approaches..

3. So, what are our options ?
 Document Store
 Apache CouchDB, MongoDB,
TerraStore
 Schema less
 Key Value
 Amazon SimpleDB , Project
Voldemort
 Column Store
 Cassandra based on Amazon
Dynamo
 Facebook, Twitter, Digg
 HyperTable based on Google
Bigtable
 Baidu
 Hbase based on Hadoop
 Bing
 Blended
 Drizzle
 Maintains relational data

4. Decisions : SQL or NoSQL ?
 Are you or your app SQL challenged ?
 With Schema or Schema-less
 Decide based on your data within your app
 Do you need ACID ?
 2 phase commit ?
 Do you need data consistency ?
 Atomic
 Eventual
 Do you need Data Persistency ?
 Pluggable: File System, Database, Custom
 In-Memory
 Do you need JOINS, complex SQL queries ?
 Do you have googlers, facebookers on your payroll ?

5. Challenges for cloud databases
 Transactional support and Referential Integrity need to
be built in yet
 Complex data access – They excel in single row
transactions, but not when a join is required
 Business Intelligence – valuable business data is locked
inside of impenetrable application data stores
 Data Integrity - does not offer either ACID support or
data reliability

6. Questions