Database files are normally stored in a proprietary binary format that can only be mounted by an instance of the relational database software that created them.

The purpose of the database instance is to to manage and deliver the data held within the database files for the users.

Modern Relational Database Management Systems (RDBMS) provide a declarative natural language abstraction layer called SQL to query the data held within the database, and provides ACID (atomicity, consistency, isolation, durability) based transactions as a key feature and benefit over other alternatives for data storage.

The topics listed below should confirm your suspicion that there is significant learning and study required to understand Exadata. Outside of the Oracle Database software (which is the same) there is a lot more complexity to operate an Exadata Machine over a tradtional database server running on Linux, UNIX, Windows. Now I know why Oracle had to change the Exadata marketing from an “appliance” to a “machine”.

I plan to update these notes once the proof of concept is complete and I fully understand all the nuances of Exadata. Until then, consider this a list of topics and source of suggested resources for further study.

Exadata Infrastructure Components

• Database Servers
• Storage Servers
• InfiniBand
• Flash Cache
• CELLBOOT USB Flash Drive

Exadata Software Components

• Oracle Automatic Storage Management (ASM)
• Oracle Real Application Clusters (RAC). Not required but sales will say it is.
• Oracle Database
• Linux Logical Volume Manager (LVM)

Connectivity

• Database Servers connect to Storage Servers using the Intelligent Database protocol (iDB) implementing the “function shipping” architecture.
• iDB use the Reliable Datagram Sockets (RDS) protocol. RDS is designed for low latency and low overhead using less significantly less CPU when compared to UDP and TCP.
• iDB is based on libskgxp.

Exadata Database Servers

• No storage devices are presented to the OS on the Exadata database servers.

Exadata Storage Servers

• Storage Indexes contain min and max values for up to eight columns.
• Storage Indexes are 1MB (default) units. Identify locations where the data is not “Reverse Index”. Best for sorted data.

Exadata Smart Scan (Offloading)

• Column Projection
• Predicate Filtering
• Storage Indexes
• Bloom Filters
• SQL Functions (most single row functions can be offloaded)
• Compression and Decompression
• Encryption/Decryption

Smart Scans not available on:

• Clustered tables
• Index Organized Tabes (IOTs)
• When ROWDEPENDENCIES is enabled

Compression Types

Basic

• Compression unit is a single Oracle block. 0% PCTFREE

OLTP (Advanced Compression)

• Compression same as basic but uses symbol table to replace repeating values. 10 % PCTFREE for updates

Hybrid Columnar Compression (Exadata Storage Only)

• QUERY LOW uses LZO compression (4x)
• QUERY HIGH uses ZLIB compression (6x)
• ARCHIVE LOW uses ZLIP compression (7x)
• ARCHIVE HIGH uses bzip2 compression (12x)

Compression should not be used on tables or partitions where data is updated due to contention.

Exadata Backup and Recovery

• RMAN incremental backups benefit from the storage servers filtering out unchanged blocks.

Recommended Reading:

• Expert Oracle Exadata
• Achieving Extreme Performance with Oracle Exadata (Osborne ORACLE Press Series)
• A Technical Overview of the Oracle Exadata Database Machine and Exadata Storage Server 
• Oracle Exadata Price List

Companies have a wealth of information systems as they continue to collect mountains of data on a daily basis. The need to house their information and have them readily available will always be there. Therefore, creating, monitoring, and maintaining the databases that house the data, pose higher challenges on the Information Technology department; in specific, the database administrators and their management. Even though now-a-days, we continue to see improvement in hardware design, operating systems stability, and database engines features; the need for database lifecycle management, best practices, and process standardization has not and will not change anytime soon.

Databases are the heart and soul of every systems/applications built or acquired within an organization. They are the center of all information, data movement, and communication of all systems. If the data is the most valuable asset of every company so is the database that houses it, making the database administration role the most critical job in IT. Therefore, effective database management is an essential task to ensure the availability, performance, recoverability, and security of such asset. Unfortunately, most companies do not realize the importance of the staff that administers their most valuable asset. They understand the need to have a staff but they always question their value and of course, their compensation. Thus, pressuring the Database Administrator staff to do nothing but, monitor the databases.

Database Administrators are highly talented individuals. They have to maintain their skills and keep up with new DBMS technology. In addition, they have to have a good understanding of all applications, data behavior, and hardware technology as they swiftly solve issues and problems with the databases they support – They are excellent problem solver individuals. So, their talent is beyond administration. But, due to the wrong perception by their management, their concentration is usually shifted to only monitoring and backing up the database, leaving several database administration roles un-played. Thus, forcing the database administrators to lose the essential skills to maintain and administer the most valuable company asset – Databases.

Every IT professional should try to answer the following questions as a health check:

• Have you ever tested recovering your production databases?
• How many times your database backup fails because of hardware or tape issues?
• How many times problems occur after a release or a migration?
• How many non-DBA users have more than read access to your production databases?
• How many times were you notified by your users of a problem before your staff knowledge of the problem?
• Do you keep current inventory of all databases?
• Do you know what your users query of your database?
• In case the data was lost, can your company survive?

This study will help your organization understand the necessary database administration roles. Most importantly, it will lay the proper roadmap for database administration.

The roadmap will guide your organization on how to be proactive rather than reactive. Catching and solving database problems before they occur proven to be more cost effective than reacting to the problem. For instance, using our roadmap will force you to monitor your space utilization. Thus, alerting of any space issues prior to your database running out of space.

Study’s Outline:

• General Assessment Process
• Understand Current Environments
• Database Management lifecycle Establishment
• Improvement Plan
• Measurement Process
• Production Maturity Process