Database Machine..

Exadata is an engineered system, broadly you have 3 important layers(Database,network and Storage)

I am writing this as and when i am studying the student guide provided in the training class

datawarehouse environment.

I have a live example in my project where we use exadata for dataware house, 

How does exadata help for datawarehouse environment ?

Support large and complex queries, offloads most of query processing to storage layer, which otherwise usually happens in the DB layer buffer cache.

Can manage massive database. utilize resource effectively. Improved compression techniques

OLTP environment.

I just learned in my training class that my company has a telecom client, where they use exadata.

How does exadata hellp for OLTP environment ?

Can support large transaction volume, large i/o  per second.

Caching frequently accessed data.

Fast response times by efficient commit processing.

Consolidating Environment.

Support mixed workloads, and can prioritize workloads. Can dynamically allocate resources based on workloads or system configuration. 

This is interesting...Imagine a bank environment...During business hours they have OLTP load and at EOD they have Batch runs. The system can be set in such a way that OLTP gets maximum resource during the day and during the night BATCH load gets the maximum resource.

Exadata prouds itself in different components and its specification

Exadat storage server - 64 bit intel based Sun Fire server, oracle provides the exadata storage software, this software imparts the database intelligence to the storage and integrates the storage to oracle database and its features.

Exada storage server is also called "Cell", There are 14 Cell in a Exadata full rack machine. Each cell is a computer with memory,cpu,network adapaters and other components normally found in the server. There would be 2 user logins in this cell server, 'celladmin' and 'cellmonitor'. 

The database and the Cell communicate with each other via a high performance infiniband network.

Storage servers are available in 2 configurations

High performance Disk

High Capacity Disk

Official Oracle doucment link here for configuration details 

Guided tour on exadata box  here (interesting).