Oracle Database Architecture
An Oracle
database is a collection of data
treated as a unit. The purpose of a database is to store and retrieve
related information. A database server is the key to solving the
problems of information management. In general, a
server
reliably manages a large amount of data in a multiuser environment so
that many users can concurrently access the same data. All this is
accomplished while delivering high performance. A database server also
prevents unauthorized access and provides efficient solutions for
failure recovery.
Oracle Database is the first database designed for enterprise grid
computing, the most flexible and cost effective way to manage
information and applications. Enterprise grid computing creates large
pools of industry-standard, modular storage and servers. With this
architecture, each new system can be rapidly provisioned from the pool
of components. There is no need for peak workloads, because capacity can
be easily added or reallocated from the resource pools as needed.
The database has
logical structures and
physical structures.
Because the physical and logical structures are separate, the physical
storage of data can be managed without affecting the access to logical
storage structures.
The section contains the following topics:
Overview of Oracle Grid Architecture
Grid computing is a new IT architecture that produces more resilient
and lower cost enterprise information systems. With grid computing,
groups of independent, modular hardware and software components can be
connected and rejoined on demand to meet the changing needs of
businesses.
The grid style of computing aims to solve some common problems with
enterprise IT: the problem of application silos that lead to under
utilized, dedicated hardware resources, the problem of monolithic,
unwieldy systems that are expensive to maintain and difficult to change,
and the problem of fragmented and disintegrated information that cannot
be fully exploited by the enterprise as a whole.
Benefits of Grid Computing Compared
to other models of computing, IT systems designed and implemented in
the grid style deliver higher quality of service, lower cost, and
greater flexibility. Higher quality of service results from having no
single point of failure, a robust security infrastructure, and
centralized, policy-driven management. Lower costs derive from
increasing the utilization of resources and dramatically reducing
management and maintenance costs. Rather than dedicating a stack of
software and hardware to a specific task, all resources are pooled and
allocated on demand, thus eliminating under utilized capacity and
redundant capabilities. Grid computing also enables the use of smaller
individual hardware components, thus reducing the cost of each
individual component and providing more flexibility to devote resources
in accordance with changing needs.
Grid Computing Defined
The grid style of computing treats collections of similar IT
resources holistically as a single pool, while exploiting the distinct
nature of individual resources within the pool. To address
simultaneously the problems of monolithic systems and fragmented
resources, grid computing achieves a balance between the benefits of
holistic resource management and flexible independent resource control.
IT resources managed in a grid include:
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Infrastructure: the hardware and software that create a data storage and program execution environment
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Applications: the program logic and flow that define specific business processes
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Information: the meanings inherent in all different types of data used to conduct business
Core Tenets of Grid Computing Two
core tenets uniquely distinguish grid computing from other styles of
computing, such as mainframe, client-server, or multi-tier:
virtualization and provisioning.
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With virtualization, individual resources (e.g. computers, disks,
application components and information sources) are pooled together by
type then made available to consumers (e.g. people or software programs)
through an abstraction. Virtualization means breaking hard-coded
connections between providers and consumers of resources, and preparing a
resource to serve a particular need without the consumer caring how
that is accomplished.
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With provisioning, when consumers request resources through a
virtualization layer, behind the scenes a specific resource is
identified to fulfill the request and then it is allocated to the
consumer. Provisioning as part of grid computing means that the system
determines how to meet the specific need of the consumer, while
optimizing operation of the system as a whole.
The specific ways in which information, application or infrastructure
resources are virtualized and provisioned are specific to the type of
resource, but the concepts apply universally. Similarly, the specific
benefits derived from grid computing are particular to each type of
resource, but all share the characteristics of better quality, lower
costs and increased flexibility.
Infrastructure Grid Infrastructure
grid resources include hardware resources such as storage, processors,
memory, and networks as well as software designed to manage this
hardware, such as databases, storage management, system management,
application servers, and operating systems.
Virtualization and provisioning of infrastructure resources mean
pooling resources together and allocating to the appropriate consumers
based on policies. For example, one policy might be to dedicate enough
processing power to a web server that it can always provide sub-second
response time. That rule could be fulfilled in different ways by the
provisioning software in order to balance the requests of all consumers.
Treating infrastructure resources as a single pool and allocating
those resources on demand saves money by eliminating under utilized
capacity and redundant capabilities. Managing hardware and software
resources holistically reduces the cost of labor and the opportunity for
human error.
Spreading computing capacity among many different computers and
spreading storage capacity across multiple disks and disk groups removes
single points of failure so that if any individual component fails, the
system as a whole remains available. Furthermore, grid computing
affords the option to use smaller individual hardware components, such
as blade servers and low cost storage, which enables incremental scaling
and reduces the cost of each individual component, thereby giving
companies more flexibility and lower cost.
Infrastructure is the dimension of grid computing that is most
familiar and easy to understand, but the same concepts apply to
applications and information.
Applications Grid
