Data Security
... at times may provide negative benefits. The diminished return with increase in resources could be tied to the theory of economics known as the Law of Diminishing Returns. Applying this theory to the current analogy, the law states that for every additional unit of a resource that is consumed, the benefit that is derived from the additional resource increases at a decreasing rate. In other words, after a certain point with additional resources, no benefit in performance is derived. In this chapter the discussions will be focused around the business requirements that drive the information technology in meeting its business goals of the enterprise. 1.2 Modern Business Requirements Modern business requirements could be classified by the abilities that the enterprise system should provide, such as availability, reliability, etc., in its day-to-day operations to provide data management to user requests. In this section the various abilities that are expected in today’s businesses are discussed along with analysis on how some of these requirements tie into the database tier of the enterprise system. Modern business requirements are classified by the abilities that a system should provide in its ultimate wisdom of existence. Figure 1.1 is a pictorial representation of the abilities that the modern enterprise system is expected to provide. Overall, these abilities could be assessed as basic requirements in every system. However, with the boom of Internet-based businesses in recent years, abilities such as availability, recoverability, scalability, manageability, and securability (security) have become a necessity. There are those additional elements, not classified under the abilities of a system, that are still vital requirements, such as throughput and response factors of the system. The primary focus of the following discussion will be with respect to the requirements of availability, scalability, manageability, and securability, but will include a brief mention of the other requirements. Securability The days when the applications were used in a small finite user community are gone. Under the client server model, the applications were used by a small named set of users and these users were identifiable as they belonged to the same organization. The Internet-based systems have databases that are accessible from all over the world. Consequently, security of data has become of utmost importance and a high-level requirement. Data is vital to a business and should be protected from hackers. Similarly, the dotcom boom has introduced a new level to sharing applications, through the application service providers (ASP) that allow many organizations and users within these organizations to access data from a common database. Data in this situation should be protected between organizations. That is, data that belongs to one organization should not be visible to others. Oracle has various levels of security available to protect data from outside hackers. Manageability and Maintainability Manageability is a broad area with many aspects. Systems being developed should be easily maintainable and manageable from every tier of the enterprise system. While it may be common to assume that maintainability and manageability is the same thing, the two terms are, in fact, different. Maintainability refers to the everyday continuance or protection of a system, such as the implementation of system and functionality level changes to the system. Manageability refers to the monitoring, tuning, and organization of the system. Manageability of business requirements entail that the application tier, network tier, database tier, etc., should be easily tunable. From the application tier perspective, there should be considerable options available to manage and monitor the health of the systems. When the business application is developed, the application should provide options to view and tune various thresholds that would help tune application performance. Similarly, development platforms selected should support tools and features that help support these requirements. The tools or methods used should offer visibility into some of the problems and internal operations of the operating system, the layered products, and the infrastructure such as the database, providing a means to understanding the issues and problems and a method for fixing them. For example, Oracle’s wait interface (V$SYSTEM_EVENT, V$SESSION_EVENT, V$SESSION_WAIT, and other tools) provides visibility to some of the internals of the Oracle database behavior, providing a better opportunity to approach the issue in a scientific manner. Every system developed is subject to continuous change throughout its life cycle, from the initial inception or implementation, to upgrades of business functionality, to upgrades of technology, etc. Maintainability of the system is the opportunity to make changes to the system. Thus development servers and database servers selected should allow for configuration changes. Scalability Scalability is typically defined in one of two ways, either as the ability to mature the system in accordance with growth in business or as the ability of the application, or enterprise system, to accept additional users in accordance with growth in business without rewriting or redesigning systems. Scalability can be vertical or horizontal (linear). When considering the growth of an enterprise system, linear scalability should be the preferred choice of configuration when compared to vertical scalability. Linear scalability can also provide vertical scalability. While vertical scalability supports more users by increasing the capacity of the existing hardware, linear scalability supports more users by increasing the number of hardware systems (nodes) participating in the configuration. From a systems perspective, a hardware clustering provides this. (A cluster is a group of independent hardware systems or nodes that are interconnected to provide a single computer source.) Linear scalability brought about by clustered hardware solutions also provides distribution of user workload among many nodes. Oracle provides a large number of features that support scalability. Combined with their respective operating systems, hardware clusters provide system level scalability on the database front. Database features, such as Real Application Cluster (RAC), which runs on a clustered operating system, take advantage of clustering. Adding the clustered database configuration to the fusion helps in providing linear scalability at the database tier of the enterprise system. Under a clustered database configuration such as RAC, as additional users start accessing the system and if there is a resource contention with Chapter1 1.2 Modern business requirements 9 the existing configuration, additional nodes and additional instances could be added to the system without much difficulty. Oracle Parallel Server (OPS), the predecessor to RAC technology, started with the feature of adding and removing instances as an Oracle solution. By taking advantage of the cluster interconnect technology to transfer and share information, RAC has taken this feature to the next level of scalability. Another functionality that scalability indirectly provides ...