RAID Definition from PC Magazine Encyclopedia
(Redundant Array of Independent Disks) A disk subsystem that increases performance or provides fault tolerance or both. RAID uses two or more physical disk drives and a RAID controller, which is plugged into motherboards that do not have RAID circuits. Today, most motherboards have built-in RAID but not necessarily every RAID configuration (see below). In the past, RAID was also accomplished by software only but was much slower. In the late 1980s, the "I" in RAID stood for "inexpensive" but was later changed to "independent." In large storage area networks (SANs), floor-standing RAID units are common with terabytes of storage and huge amounts of cache memory. RAID 0 - Disk Striping for Performance (Popular) Widely used for gaming, disk striping interleaves data across multiple drives for performance. RAID 1 - Mirroring for Fault Tolerance (Popular) Widely used, RAID 1 writes two drives at the same time. Big RAID Little RAID Arco was first to provide RAID 1 on IDE drives rather than SCSI.
RAID tutorial - the benefits of using RAID
RAID (Redundant Array of Inexpensive Disks) is a system developed whereby two or more disks are physically linked together to form a single logical, large capacity storage device that offers a number of advantages over conventional hard disk storage devices: superior performanceimproved resiliencylower costs There are a number of RAID levels, each focusing on one or other of these advantages, either singly or in combination. The two principal techniques used are: striping, andmirroring Striping is the technique to provide increased performance. Mirroring was the first real implementation of RAID, typically requiring two individual drives of similar capacity. For many years RAID was the preserve of enterprise, server-based systems. Here, we’re implementing RAID 1 for the purpose of improved resiliency. RAID 1 offers a simple and effective solution ……. transparently! Rating: 10.0/10 (2 votes cast) RAID tutorial - the benefits of using RAID, 10.0 out of 10 based on 2 ratings
Standard RAID levels
In computer storage, the standard RAID levels comprise a basic set of RAID configurations that employ the techniques of striping, mirroring, or 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 and its variants (mirroring), RAID 5 (distributed parity), and RAID 6 (dual parity). 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.[1] RAID 0[edit] Diagram of a RAID 0 setup RAID 0 (also known as a stripe set or striped volume) splits data evenly across two or more disks (striped), without parity information and with speed as the intended goal. A RAID 0 setup can be created with disks of differing sizes, but the storage space added to the array by each disk is limited to the size of the smallest disk. Performance[edit] RAID 1[edit] Diagram of a RAID 1 setup RAID 2[edit] .
▶ Multiple hard drives working together: All about RAID setups
Stevey, admitted confused by the benefits of RAIDs, asked the Answer Line forum to explain these hard drive groups. A Redundant Array of Independent Disks (RAID) puts multiple hard drives together to improve on what a single drive can do on its own. Depending on how you configure a RAID, it can increase your computer's speed while giving you a single "drive" that can hold as much as all of the drives combined. Or you can use a RAID to increase reliability, so that your computer will keep working after a hard drive crash. Some RAIDS allow you to do both. [Email your tech questions to answer@pcworld.com or post them on the PCW Answer Line forum.] Here are three of the most popular RAID configurations: This type of RAID turns the two or more drives inside of it into one bigger, faster storage unit. When you save a file, a RAID 0 splits it into sections and distributes it across the various drives. It also gives you a lot of storage. But don't confuse RAID 1 with a real backup.
RAID
RAID (originally redundant array of inexpensive disks; now commonly redundant array of independent disks) is a data storage virtualization technology that combines multiple disk drive components into a logical unit for the purposes of data redundancy or performance improvement.[1] History[edit] Although not yet using that terminology, each of the five levels of RAID named in the paper were well established in the art prior to the paper's publications, for example: Around 1983, DEC began shipping subsystem mirrored RA8X disk drives (now known as RAID 1) as part of its HSC50 subsystem.[3]Around 1988, the Thinking Machines DataVault used error correction codes (now known as RAID 2) in an array of disk drives.[4] A similar approach was used in the 1970s on the IBM 3330.[5]In 1977, Norman Ken Ouchi at IBM filed a patent disclosing what was subsequently named RAID 4.[6]In 1986, Clark et al. at IBM filed a patent disclosing what was subsequently named RAID 5.[7] Concept[edit] Standard levels[edit]
RAID storage explained
This information is also available as a PDF download. Since I've been doing a lot of coverage of storage technology both for the enterprise and for the home lately, I thought I should give an explanation of what RAID storage is. I won't go in to every RAID type under the sun, I just want to cover the basic types of RAID and what the benefits and tradeoffs are. RAID was originally defined as Redundant Array of Inexpensive Drives, but RAID setups were traditionally very expensive so the definition of "I" became Independent. The costs have recently come down significantly because of commoditization and RAID features are now embedded on to most higher-end motherboards. Fault tolerance defined: Basic fault tolerance in the world of storage means your data is intact even if one or more hard drives fails. Storage performance defined: There are two basic metrics of performance in the world of storage. MirroringStripingStriping with parity Basic RAID Levels defined
RAID Made Easy
What is RAID, why do you need it, and what are all those mode numbers that are constantly bandied about? RAID stands for “Redundant Array of Independent Disks” or “Redundant Array of Inexpensive Disks,” depending on who you talk to. Note that the word array is included in the acronym, so saying “RAID array,” as a lot of people do, is redundant. Back when hard drives were less capacious and more expensive, RAID was created to combine multiple, less-expensive drives into a single, higher-capacity and/or faster volume. Redundancy is important for a small business, as drive failure does happen. RAID has levels, or methods by which the drives are ganged together; commonly people refer to levels by number. RAID 0 Picture the 0 in the “RAID 0” name as an oval racetrack and you’ve divined its primary purpose: Faster performance. RAID 1 RAID 1 writes and reads the same data to pairs of drives; it’s also referred to as mirroring. RAID 5 This RAID mode offers both speed and data redundancy.
