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Oracle Data Guard
The software which Oracle Corporation markets as Oracle Data Guard forms an extension to the Oracle relational database management system (RDBMS). It aids in establishing and maintaining secondary standby databases as alternative/supplementary repositories to production primary databases. Oracle provides both graphical user interface (GUI) and command-line (CLI) tools for managing Data Guard configurations. Data Guard supports both physical standby and logical standby sites. Oracle Corporation makes Data Guard available only as a bundled feature included within its "Enterprise Edition" of the Oracle RDBMS. With appropriately set-up Data Guard operations, DBAs can facilitate failovers or switchovers to alternative hosts in the same or alternative locations. Configurations For the purposes of Data Guard, each Oracle database functions either in a primary database role or in a standby database role - with the ability to transition from one role to the other. Physical stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Corporation
Oracle Corporation is an American multinational computer technology corporation headquartered in Austin, Texas. In 2020, Oracle was the third-largest software company in the world by revenue and market capitalization. The company sells database software and technology (particularly its own brands), cloud engineered systems, and enterprise software products, such as enterprise resource planning (ERP) software, human capital management (HCM) software, customer relationship management (CRM) software (also known as customer experience), enterprise performance management (EPM) software, and supply chain management (SCM) software. History Larry Ellison co-founded Oracle Corporation in 1977 with Bob Miner and Ed Oates under the name Software Development Laboratories (SDL). Ellison took inspiration from the 1970 paper written by Edgar F. Codd on relational database management systems ( RDBMS) named "A Relational Model of Data for Large Shared Data Banks." He heard about the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Layer
In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers. Functions The network layer provides the means of transferring variable-length network packets from a source to a destination host via one or more networks. Within the service layering semantics of the OSI network architecture, the network layer responds to service requests from the transport layer and issues service requests to the data link layer. Functions of the network layer include: ; Connectionless communication : For example, IP is connectionless, in that a data packet can travel from a sender to a recipient without the recipient having to send an acknowledgement. Connection-oriented protocols exist at other, higher layers of the OSI model. ; Host addressing :Every host in the network must have a unique address that determines where it is. This address is normally assigned from a hierar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preventive Maintenance
The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installations. Over time, this has come to include multiple wordings that describe various cost-effective practices to keep equipment operational; these activities occur either before or after a failure. Definitions Maintenance functions can defined as maintenance, repair and overhaul (MRO), and MRO is also used for maintenance, repair and operations. Over time, the terminology of maintenance and MRO has begun to become standardized. The United States Department of Defense uses the following definitions:Federal Standard 1037C and from MIL-STD-188 and from the Department of Defense Dictionary of Military and Associated Terms * Any activity—such as tests, measurements, replacements, adjustments, and repairs—intended to retain or restore a func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upgrade
Upgrading is the process of replacing a product with a newer version of the same product. In computing and consumer electronics an upgrade is generally a replacement of hardware, software or firmware with a newer or better version, in order to bring the system up to date or to improve its characteristics. Computing and consumer electronics Examples of common hardware upgrades include installing additional memory (RAM), adding larger hard disks, replacing microprocessor cards or graphics cards, and installing new versions of software. Many other upgrades are possible as well. Common software upgrades include changing the version of an operating system, of an office suite, of an anti-virus program, or of various other tools. Common firmware upgrades include the updating of the iPod control menus, the Xbox 360 dashboard, or the non-volatile flash memory that contains the embedded operating system for a consumer electronics device. Users can often download software and firmware u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disaster Recovery
Disaster recovery is the process of maintaining or reestablishing vital infrastructure and systems following a natural or human-induced disaster, such as a storm or battle.It employs policies, tools, and procedures. Disaster recovery focuses on the information technology (IT) or technology systems supporting critical business functions as opposed to business continuity. This involves keeping all essential aspects of a business functioning despite significant disruptive events; it can therefore be considered a subset of business continuity. Disaster recovery assumes that the primary site is not immediately recoverable and restores data and services to a secondary site. IT service continuity IT Service Continuity (ITSC) is a subset of business continuity planning (BCP) that focuses on Recovery Point Objective (RPO) and Recovery Time Objective (RTO). It encompasses IT disaster recovery planning and wider IT resilience planning. It also incorporates IT infrastructure and services rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Databases
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance. A database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Availability
High availability (HA) is a characteristic of a system which aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period. Modernization has resulted in an increased reliance on these systems. For example, hospitals and data centers require high availability of their systems to perform routine daily activities. Availability refers to the ability of the user community to obtain a service or good, access the system, whether to submit new work, update or alter existing work, or collect the results of previous work. If a user cannot access the system, it is – from the user's point of view – ''unavailable''. Generally, the term ''downtime'' is used to refer to periods when a system is unavailable. Principles There are three principles of systems design in reliability engineering which can help achieve high availability. # Elimination of single points of failure. This means adding or building redundancy into the system so that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redo Log
Undo is an interaction technique which is implemented in many computer programs. It erases the last change done to the document, reverting it to an older state. In some more advanced programs, such as graphic processing, undo will negate the last command done to the file being edited. With the possibility of undo, users can explore and work without fear of making mistakes, because they can easily be undone. The expectations for undo are easy to understand: to have a predictable functionality, and to include all "undoable" commands. Usually undo is available until the user undoes all executed operations. But there are some actions which are not stored in the undo list, and thus they cannot be undone. For example, ''save file'' is not undoable, but is queued in the list to show that it was executed. Another action which is usually not stored, and thus not undoable, is ''scrolling'' or ''selection''. The opposite of undo is ''redo''. The redo command reverses the undo or advances t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Net
In the field of database computing, Oracle Net Services consists of sets of software which enable client applications to establish and maintain network sessions with Oracle Database servers. Since Oracle databases operate in and across a variety of software and hardware environments, Oracle Corporation supplies high-level transparent networking facilities with the intention of providing networking functionality regardless of differences in nodes and protocols. Terminology * network service name (NSN): " simple name for a service that resolves to a connect descriptor" For example: sales.acme.co.uk Components Oracle Corporation defines Oracle Net Services as comprising: * Oracle net * listener * Oracle Connection Manager * Oracle Net Configuration assistant * Oracle Net Manager Oracle Net Oracle Net, a proprietary networking stack, runs both on client devices and on Oracle database servers in order to set up and maintain connections and messaging between client appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Database
Oracle Database (commonly referred to as Oracle DBMS, Oracle Autonomous Database, or simply as Oracle) is a multi-model database management system produced and marketed by Oracle Corporation. It is a database commonly used for running online transaction processing (OLTP), data warehousing (DW) and mixed (OLTP & DW) database workloads. Oracle Database is available by several service providers on-prem, on-cloud, or as a hybrid cloud installation. It may be run on third party servers as well as on Oracle hardware (Exadata on-prem, on Oracle Cloud or at Cloud at Customer). History Larry Ellison and his two friends and former co-workers, Bob Miner and Ed Oates, started a consultancy called Software Development Laboratories (SDL) in 1977. SDL developed the original version of the Oracle software. The name ''Oracle'' comes from the code-name of a CIA-funded project Ellison had worked on while formerly employed by Ampex. Releases and versions Oracle products follow a custom r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switchover
Switchover is the manual switch from one system to a redundant or standby computer server, system, or network upon the failure or abnormal termination of the previously active server, system, or network, or to perform system maintenance, such as installing patches, and upgrading software or hardware. Automatic switchover of a redundant system on an error condition, without human intervention, is called failover. Manual switchover on error would be used if automatic failover is not available, possibly because the overall system is too complex. See also * Safety engineering * Data integrity * Fault-tolerance * HA Clusters * Business continuity planning Business continuity may be defined as "the capability of an organization to continue the delivery of products or services at pre-defined acceptable levels following a disruptive incident", and business continuity planning (or business continuity a ... References Engineering failures Fault-tolerant computer systems {{c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Failover
Failover is switching to a redundant or standby computer server, system, hardware component or network upon the failure or abnormal termination of the previously active application, server, system, hardware component, or network in a computer network. Failover and switchover are essentially the same operation, except that failover is automatic and usually operates without warning, while switchover requires human intervention. Systems designers usually provide failover capability in servers, systems or networks requiring near-continuous availability and a high degree of reliability. At the server level, failover automation usually uses a " heartbeat" system that connects two servers, either through using a separate cable (for example, RS-232 serial ports/cable) or a network connection. As long as a regular "pulse" or "heartbeat" continues between the main server and the second server, the second server will not bring its systems online. There may also be a third "spare parts" se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
