System Catalog › Database Appliances › ORACLE: ORACLE Database Appliance

ORACLE: ORACLE Database Appliance

Functional Overview

ORACLE is a database appliance based on the Oracle Database Server 10g R2 Express Edition (http://www.oracle.com/technetwork/database/express-edition/overview/index.html). It provides an easy way to add a database to any application. ORACLE is an entry-level, small-footprint database that's free to develop, deploy, and distribute; and simple to administer. Oracle Database XE is a great starter database for:

• Developers working on PHP, Java, .NET, XML, and Open Source applications
• DBAs who need a free, starter database for training and deployment
• Independent Software Vendors (ISVs) and hardware vendors who want a starter database to distribute free of charge
• Educational institutions and students who need a free database for their curriculum

With Oracle Database XE, you can now develop and deploy applications with a powerful, proven, industry-leading infrastructure, and then upgrade when necessary without costly and complex migrations.

ORACLE stores the database on an application-defined volume that can be configured on each ORACLE instance. ORACLE creates an empty database instance when it starts on an empty volume. The ORACLE database volume cannot be shared among multiple ORACLE instances (one database volume per ORACLE instance).

ORALCE clients access the configured database through the in terminal. The database requests are processed and completed back through the same terminal. ORACLE allows any valid Oracle user to access the database through the in terminal (the appliance has two preconfigured superuser roles: standard 'SYSTEM' and 'SYS'). ORACLE can be configured with the maximum number of concurrent connections supported through in.

ORACLE also has the ability to maintain a database log accessible through the log terminal. The log is useful for tracking database information and error logging. In addition, various database statistics and debugging information may also be enabled to help with profiling database access patterns and diagnosing problems/errors.

Boundary

Resources

Notes:

• Memory should be increased based on two main factors: number of concurrent users and database size. Typically, ORACLE can support about 80 concurrent users per 512 MB of memory. The larger the database, the more memory ORACLE should have for processing. For example, ORACLE should be configured with at least 1G of memory for a 10G database - more than 1G for better performance.

ORACLE can be started with any system resources, but XE will store up to 4GB of user data, use up to 1GB of memory, and use one CPU on the host appliance.

Terminals

The default interface is enabled. It is intended for diagnostics and troubleshooting (over SSH). Future versions of this appliance may disable SSH access.

Volumes

Notes:

• The data volume must exclusively dedicated to the ORACLE instance (cannot be shared with other appliances). 2GB of size minimum.

The swap volume must exclusively dedicated to the ORACLE instance (cannot be shared with other appliances). 1.5GB of size minimum.

Properties

None of the ORACLE properties are case sensitive excluding file names and paths.

Logging Properties:

Note: The ORACLE appliance will fail to start if logging is enabled and the log terminal is not connected.

Custom Counters

The ORACLE appliance reports the following custom counters through the mon terminal. These counters belong to the ORACLE counter group:

Possible Startup Errors

In case of appliance startup failure, the following errors may be logged to the system log:

Dashboard Messages

In cases where critical errors are encountered that may require user attention, ORACLE logs messages to the grid's dashboard as follows:

These messages are logged only one time once the free disk space amount drops below the threshold.

Typical Usage

Simple two-tier application (web database application)

The following diagram shows a typical usage of the ORACLE appliance in a two-tier web application geared toward a lot of users executing simple queries:

Appliances in use:

• usr - input gateway
• srv - web server with active content (for example, CGI scripts)
• db - Oracle XE database appliance

Client requests arrive on the usr gateway. The gateway forwards the requests to the web server, which serves the request. When script (for example, Perl or PHP) on srv need to access persistent data, it uses the db appliance through the db terminal.

In this example, the database used with db is not read-only and many users may access it through srv executing simple queries. As such, db is configured to use 512MB of memory. Also, the database does not keep any database error log files (the log terminal is not connected).

Note: The data volume must also be configured on db and the content volume must be configured on srv. To create application volumes that can be used here, see the User Volumes online help topic.

Notes

• ORACLE allows any valid ORACLE user to access the database (roles 'SYSTEM' and 'SYS' are preconfigured as superuser; new roles could be created). The database can only be accessed either through the in terminal or locally on the ORACLE appliance itself.
• Volume requirements
  • Verify that the data volume is 2G or bigger, otherwise Oracle will fail to start.
  • Verify that the swap volume is 1.5G or bigger, otherwise Oracle will fail to start.
  • You can leave the volume empty (just created). ORACLE will create an empty instance on the volume when it is started.
  • The volume contains only the database data. The data can be moved by copying all files to a new (for example, larger) volume.
  • Oracle configuration files on the data volume are copied from /appliance/oracle directory.
• The appliance connected to ORACLE is responsible for creating its own schemas and tables if they do not exist.
• References:
  • http://www.oracle.com -- Oracle's website
  • http://www.oracle.com/technetwork/database/express-edition/overview/index.html -- Oracle XE product section

Open source and 3rd party software used inside of the appliance

The following open source 3rd party software is used in addition to that software found on the appliance base class (LUX5 is the base class).