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Redundant Array Of Inexpensive Servers
A Redundant Array of Inexpensive Servers (RAIS) or Redundant Array of Independent Nodes (RAIN) is the use of multiple servers to maintain service if one server fails. This is similar in concept to how RAID turns a cluster of ordinary disks into a single block device. RAIS was designed to provide the benefits of a symmetric multiprocessor system (SMP) at the entry cost of computer clusters. The term may imply some kind of load balancing between the servers. Technology RAIS is a simple, high performance, mainframe-grade alternative to more expensive enterprise computing infrastructure solutions. It turns an array of ordinary servers into a single virtual machine, similar in concept to how RAID turns a cluster of ordinary disks into a single block device. Every RAIS node is a stateless computing unit. RAIS stripes and mirrors application code and memory across an array of ordinary servers using the standard RAID schemata of level 0, level 1, level 5, level 1+0. This is possi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Server (computing)
In computing, a server is a piece of computer hardware or software (computer program) that provides functionality for other programs or devices, called " clients". This architecture is called the client–server model. Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client. A single server can serve multiple clients, and a single client can use multiple servers. A client process may run on the same device or may connect over a network to a server on a different device. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. Client–server systems are usually most frequently implemented by (and often identified with) the request–response model: a client sends a request to the server, which performs some action and sends a response back to the client, typically with a result or acknowledg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAID
Raid, RAID or Raids may refer to: Attack * Raid (military), a sudden attack behind the enemy's lines without the intention of holding ground * Corporate raid, a type of hostile takeover in business * Panty raid, a prankish raid by male college students on the living quarters of female students to steal panties as trophies * Police raid, a police action involving the entering of a house with the intent to capture personnel or evidence, often taking place early in the morning *Union raid, when an outsider trade union takes over the membership of an existing union Arts, entertainment, and media Films * ''Raid'' (1947 film), an East German film * ''Raid'' (2003 film), a 2003 Finnish film * ''Raid'' (2018 film), an Indian period crime thriller Gaming * Raid (gaming), a type of mission in a video game where a large number of people combine forces to defeat a powerful enemy * ''Raid'' (video game), a Nintendo Entertainment System title released by Sachen in 1989 * '' Raid over Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetric Multiprocessor System
Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes. Most multiprocessor systems today use an SMP architecture. In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors. Professor John D. Kubiatowicz considers traditionally SMP systems to contain processors without caches. Culler and Pal-Singh in their 1998 book "Parallel Computer Architecture: A Hardware/Software Approach" mention: "The term SMP is widely used but causes a bit of confusion. ..The more precise description of what is intended by SMP is a shared memory multiprocessor where the cost of accessing a memory location ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Cluster
A computer cluster is a set of computers that work together so that they can be viewed as a single system. Unlike grid computers, computer clusters have each node set to perform the same task, controlled and scheduled by software. The components of a cluster are usually connected to each other through fast local area networks, with each node (computer used as a server) running its own instance of an operating system. In most circumstances, all of the nodes use the same hardware and the same operating system, although in some setups (e.g. using Open Source Cluster Application Resources (OSCAR)), different operating systems can be used on each computer, or different hardware. Clusters are usually deployed to improve performance and availability over that of a single computer, while typically being much more cost-effective than single computers of comparable speed or availability. Computer clusters emerged as a result of convergence of a number of computing trends including t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Load Balancing (computing)
In computing, load balancing is the process of distributing a set of tasks over a set of resources (computing units), with the aim of making their overall processing more efficient. Load balancing can optimize the response time and avoid unevenly overloading some compute nodes while other compute nodes are left idle. Load balancing is the subject of research in the field of parallel computers. Two main approaches exist: static algorithms, which do not take into account the state of the different machines, and dynamic algorithms, which are usually more general and more efficient but require exchanges of information between the different computing units, at the risk of a loss of efficiency. Problem overview A load-balancing algorithm always tries to answer a specific problem. Among other things, the nature of the tasks, the algorithmic complexity, the hardware architecture on which the algorithms will run as well as required error tolerance, must be taken into account. Therefore c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Application Code
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This glossary of computer software terms lists the general terms related to computer software, and related fields, as commonly used in Wikipedia articles. Glossary See also * Outline of computer programming * Outline of software * Software References software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Array Controller
A disk array controller is a device that manages the physical disk drives and presents them to the computer as logical units. It almost always implements hardware RAID, thus it is sometimes referred to as RAID controller. It also often provides additional disk cache. ''Disk array controller'' is often improperly shortened to ''disk controller''. The two should not be confused as they provide very different functionality. Front-end and back-end side A disk array controller provides front-end interfaces and back-end interfaces. * Back-end interface communicates with controlled disks. Hence protocol is usually ATA (a.k.a. PATA), SATA, SCSI, FC or SAS. * Front-end interface communicates with a computer's host adapter (HBA, Host Bus Adapter) and uses: ** one of ATA, SATA, SCSI, FC; these are popular protocols used by disks, so by using one of them a controller may transparently emulate a disk for a computer ** somewhat less popular protocol dedicated for a specific solution: FICO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Data Format
The SNIA Common RAID Disk Data Format (DDF) defines a standard data structure describing how data is formatted across disks in a RAID group. The DDF structure allows a basic level of interoperability between different suppliers of RAID technology. The Common RAID DDF structure benefits storage users by enabling in-place data migration or recovery after controller failure using systems from different vendors. DDF is an external metadata format that is compatible with the mdraid subsystem in the Linux kernel. The mdadm mdadm is a Linux utility used to manage and monitor software RAID devices. It is used in modern Linux distributions in place of older software RAID utilities such as raidtools2 or raidtools. mdadm is free software originally maintained by, ... command-line utility is a part of the mdraid subsystem. References External links Common RAID Disk Data Format (DDF) Specification v2.0Using DDF volumes with Linux Kernel RAID {{Compu-storage-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinum Volume Manager
Vinum is a logical volume manager, also called software RAID, allowing implementations of the RAID-0, RAID-1 and RAID-5 models, both individually and in combination. The original Vinum was part of the base distribution of the FreeBSD operating system since 3.0, and also NetBSD between 2003-10-10 and 2006-02-25, as well as descendants of FreeBSD, including DragonFly BSD; in more recent versions of FreeBSD, it has been replaced with gvinum, which was first introduced around FreeBSD 6. Vinum source code is maintained in the FreeBSD and DragonFly source trees. Vinum supports RAID levels 0, 1, 5, and JBOD. Vinum was inspired by Veritas Volume Manager. Vinum is invoked as gvinum (GEOM Vinum) on FreeBSD version 5.4 and up. In modern FreeBSD, it may be considered to be a legacy volume manager; modern alternatives being GEOM and ZFS. In NetBSD, it has been removed before NetBSD 4.0 due to lack of interest and maintenance; RAIDframe was cited as providing similar functionality. In DragonF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
