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Disk Mirroring
In Data storage device, data storage, disk mirroring is the Replication (computing), replication of logical disk volumes onto separate physical hard disks in Real-time computing, real time to ensure continuous availability. It is most commonly used in RAID 1. A mirrored volume is a complete logical representation of separate volume copies. In a IT disaster recovery, disaster recovery context, mirroring data over long distance is referred to as storage replication. Depending on the technologies used, replication can be performed synchronously, Asynchronous communication, asynchronously, semi-synchronously, or point-in-time. Replication is enabled via microcode on the disk array controller or via Server (computing), server software. It is typically a proprietary solution, not compatible between various data storage device vendors. Mirroring is typically only synchronous. Synchronous writing typically achieves a recovery point objective (RPO) of zero lost data. Asynchronous replica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raid1 Version For Wiki
In computer storage, the standard RAID levels comprise a basic set of RAID ("redundant array of independent disks" or "redundant array of inexpensive disks") configurations that employ the techniques of Data striping, striping, Disk mirroring, mirroring, or Parity bit#RAID array, parity to create large reliable data stores from multiple general-purpose computer hard disk drives (HDDs). The most common types are RAID 0 (striping), RAID 1 (mirroring) and its variants, RAID 5 (distributed parity), and RAID 6 (dual parity). Multiple RAID levels can also be combined or ''#Nested RAID, nested'', for instance RAID 10 (striping of mirrors) or RAID 01 (mirroring stripe sets). RAID levels and their associated data formats are standardized by the Storage Networking Industry Association (SNIA) in the Common RAID Disk Drive Format (DDF) standard. The numerical values only serve as identifiers and do not signify performance, reliability, generation, hierarchy, or any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
File Shadowing
In computing, file copying is the act of creating a new file such that it has the same content as an existing file. The operation is sometimes called ''cloning''. Generally, an operating system command-line shell provides for file copying via commands cp, copy and similar variants. mv also copies files but only when the source and destination are on different file systems. Windows also provides includes the more advanced tools: Robocopy and xcopy. Many operating systems also provide for copying files via a graphical user interface, such as a file manager. It may provide for copy-and-paste and drag-and-drop user experience. Notable third-party utilities: * FastCopy * Rclone * RichCopy * rsync * TeraCopy * Ultracopier Shadow copy Shadowing describes the process of maintaining a copy of a set of files, a.k.a. to mirror files in a separate physical location. Depending on the reasons behind the shadow operation, this location may be as close as the BIOS chi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirror Site
Mirror sites or mirrors are replicas of other websites. The concept of mirroring applies to network services accessible through any protocol, such as HTTP or FTP. Such sites have different URLs than the original site, but host identical or near-identical content. Mirror sites are often located in a different geographic region than the original, or upstream site. The purpose of mirrors is to reduce network traffic, improve access speed, ensure availability of the original site for technical or political reasons, or provide a real-time backup of the original site. Mirror sites are particularly important in developing countries, where internet access may be slower or less reliable. Mirror sites were heavily used on the early internet, when most users accessed through dialup and the Internet backbone had much lower bandwidth than today, making a geographically-localized mirror network a worthwhile benefit. Download archives such as Info-Mac, Tucows and CPAN maintained worldwide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Replicated Block Device
Distributed Replicated Block Device (DRBD) is a distributed replicated storage system for the Linux platform. It mirrors block devices between multiple hosts, functioning transparently to applications on the host systems. This replication can involve any type of block device, such as hard drives, partitions, RAID setups, or logical volumes. DRBD is implemented as a kernel driver, several userspace management applications, and some shell scripts. DRBD is traditionally used in high availability (HA) computer clusters, but beginning with DRBD version 9, it can also be used to create larger software defined storage pools with a focus on cloud integration. The DRBD software is free software released under the terms of the GNU General Public License version 2. DRBD is part of the Lisog open source stack initiative. Mode of operation DRBD layers logical block devices (conventionally named /dev/drbd''X'', where ''X'' is the device minor number) over existing local block devices on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Cloning
Disk cloning is the process of duplicating all data on a Digital Storage, digital storage drive, such as a Hard disk drive, hard disk or Solid-state drive, solid state drive, using hardware or software techniques. Unlike file copying, disk cloning also duplicates the File system, filesystems, Disk partitioning, partitions, drive meta data and slack space on the drive. Common reasons for cloning a drive include; data backup and recovery; duplicating a computer's configuration for mass deployment and for preserving data for digital forensics purposes. Drive cloning can be used in conjunction with Disk imaging, drive imaging where the cloned data is saved to one or more files on another drive rather than copied directly to another drive. Background Disk cloning occurs by copying the contents of a drive called the source drive. While called "disk cloning", any type of storage medium that connects to the computer via USB, NVMe or SATA can be cloned. A small amount of data is read and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Standby
A hot spare or warm spare or hot standby is a component used as a failover mechanism to provide reliability in system configurations. The hot spare is active and connected as part of a working system. When a key component fails, the hot spare is switched into operation. More generally, a hot standby can be used to refer to any device or system that is held in readiness to overcome an otherwise significant start-up delay. Examples Examples of hot spares are components such as A/V switches, computers, network printers, and hard disks. The equipment is powered on, or considered "hot," but not actively functioning in (i.e. used by) the system. Electrical generators may be held on hot standby, or a steam train may be held at the shed fired up (literally hot) ready to replace a possible failure of an engine in service. Explanation In designing a reliable system, it is recognized that there will be failures. At the extreme, a complete system can be duplicated and kept up to date� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Swap
Hot swapping is the replacement or addition of components to a computer system without stopping, shutting down, or rebooting the system. Hot plugging describes only the addition of components to a running computer system. Components which have such functionality are said to be ''hot-swappable'' or ''hot-pluggable''; likewise, components which do not are ''cold-swappable'' or ''cold-pluggable''. Although the broader concept of hot swapping can apply to electrical or mechanical systems, it is usually mentioned in the context of computer systems. An example of hot swapping is the express ability to pull a Universal Serial Bus (USB) peripheral device, such as a thumb drive, mouse, keyboard, or printer out of a computer's USB slot without powering down the computer first. Most desktop computer hardware, such as CPUs and memory, are only cold-pluggable. However, it is common for mid to high-end servers and mainframes to feature hot-swappable capability for hardware components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux Foundation
The Linux Foundation (LF) is a non-profit organization established in 2000 to support Linux development and open-source software projects. Background The Linux Foundation started as Open Source Development Labs in 2000 to standardize and promote the open-source operating system kernel Linux. It merged with Free Standards Group in 2007. The foundation has since evolved to promote open-source projects beyond the Linux OS as a "foundation of foundations" that hosts a variety of projects spanning topics such as cloud computing, cloud, networking, blockchain, and hardware. The foundation also hosts annual educational events among the Linux community, including the Linux Kernel Developers Summit and the Open Source Summit. Projects , the total economic value of the development costs of Linux Foundation Collaborative Projects was estimated at $5 billion. Community stewardship For the Linux kernel community, the Linux Foundation hosts its IT infrastructure and organizes #Confe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Btrfs
Btrfs (pronounced as "better F S", "butter F S", "b-tree F S", or "B.T.R.F.S.") is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager (distinct from Linux's LVM), developed together. It was created by Chris Mason in 2007 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel. Btrfs is intended to address the lack of pooling, snapshots, integrity checking, data scrubbing, and integral multi-device spanning in Linux file systems. Mason, the principal Btrfs author, stated that its goal was "to let inuxscale for the storage that will be available. Scaling is not just about addressing the storage but also means being able to administer and to manage it with a clean interface that lets people see what's being used and makes it more reliable". History The core data structure of Btrfsthe copy-on-write B-treewas originally proposed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Hat
Red Hat, Inc. (formerly Red Hat Software, Inc.) is an American software company that provides open source software products to enterprises and is a subsidiary of IBM. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina, with other offices worldwide. Red Hat has become associated to a large extent with its enterprise operating system Red Hat Enterprise Linux. With the acquisition of open-source enterprise middleware vendor JBoss, Red Hat also offers Red Hat Virtualization (RHV), an enterprise virtualization product. Red Hat provides storage, operating system platforms, middleware, applications, management products, support, training, and consulting services. Red Hat creates, maintains, and contributes to many free software projects. It has acquired the codebases of several proprietary software products through corporate mergers and acquisitions, and has released such software under open source licenses. , Red Hat is the second largest co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Device Mapper
The device mapper is a framework provided by the Linux kernel for mapping physical block devices onto higher-level ''virtual block devices''. It forms the foundation of the logical volume manager (LVM), software RAIDs and dm-crypt disk encryption, and offers additional features such as file system snapshots. Device mapper works by passing data from a virtual block device, which is provided by the device mapper itself, to another block device. Data can be also modified in transition, which is performed, for example, in the case of device mapper providing disk encryption or simulation of unreliable hardware behavior. This article focuses on the device mapper implementation in the Linux kernel, but the device mapper functionality is also available in both NetBSD and DragonFly BSD. Usage Applications (like LVM2 and Enterprise Volume Management System (EVMS)) that need to create new mapped devices talk to the device mapper via the libdevmapper.so shared library, which in tur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
