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Introduction to Oracle Database
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. Overview of Oracle Grid ArchitectureThe Oracle
grid architecture pools large numbers of servers, storage, and networks into a
flexible, on-demand computing resource for enterprise computing needs. The grid
computing infrastructure continually analyzes demand for resources and adjusts
supply accordingly. For example,
you could run different applications on a grid of several linked database
servers. When reports are due at the end of the month, the database
administrator could automatically provision more servers to that application to
handle the increased demand. Grid computing uses sophisticated workload management that makes it possible for applications to share resources across many servers. Data processing capacity can be added or removed on demand, and resources within a location can be dynamically provisioned. Web services can quickly integrate applications to create new business processes.
Difference between a cluster and a grid Clustering is one technology used to create a
grid infrastructure. Simple clusters have static resources for specific
applications by specific owners. Grids, which can consist of multiple clusters,
are dynamic resource pools shareable among many different applications and
users. A grid does not assume that all servers in the grid are running the same
set of applications. Applications can be scheduled and migrated across servers
in the grid. Grids share resources from and among independent system owners. At the
highest level, the idea of grid computing is computing as a utility. In other
words, you should not care where your data resides, or what computer processes
your request. You should be able to request information or computation and have
it delivered - as much as you want, and whenever you want. This is analogous to
the way electric utilities work, in that you don't know where the generator is,
or how the electric grid is wired, you just ask for electricity, and you get
it. The goal is to make computing a utility, a commodity, and ubiquitous. Hence the name, The Grid. This view of utility computing is,
of course, a "client side" view. From the
"server side", or behind the scenes, the grid is about resource
allocation, information sharing, and high availability. Resource allocation
ensures that all those that need or request resources are getting what they
need, that resources are not standing idle while requests are going unserviced. Information sharing makes sure that the
information users and applications need is available where and when it is
needed. High availability features guarantee all the data and computation is
always there, just like a utility company always provides electric power. Responsibilities of Database AdministratorsEach database requires at least one
database administrator (DBA). An Oracle Database system can be large and can
have many users. Therefore, database administration is sometimes not a
one-person job, but a job for a group of DBAs who share responsibility. A
database administrator's responsibilities can include the following tasks:
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