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Diagram of a RAID 1 setup. RAID 1 consists of an exact copy (or mirror) of a set of data on two or more disks; a classic RAID 1 mirrored pair contains two disks.This configuration offers no parity, striping, or spanning of disk space across multiple disks, since the data is mirrored on all disks belonging to the array, and the array can only be as big as the smallest member disk.
Nested RAID levels, also known as hybrid RAID, combine two or more of the standard RAID levels (where "RAID" stands for "redundant array of independent disks" or "redundant array of inexpensive disks") to gain performance, additional redundancy or both, as a result of combining properties of different standard RAID layouts.
There are five different RAID-Z modes: RAID-Z0 (similar to RAID 0, offers no redundancy), RAID-Z1 (similar to RAID 5, allows one disk to fail), RAID-Z2 (similar to RAID 6, allows two disks to fail), RAID-Z3 (a RAID 7 [a] configuration, allows three disks to fail), and mirror (similar to RAID 1, allows all but one of the disks to fail). [22]
RAID (/ r eɪ d /; redundant array of inexpensive disks or redundant array of independent disks) [1] [2] is a data storage virtualization technology that combines multiple physical data storage components into one or more logical units for the purposes of data redundancy, performance improvement, or both.
Those RAID systems made their way to the consumer market, for users wanting the fault-tolerance of RAID without investing in expensive SCSI drives. Fast consumer drives make it possible to build RAID systems at lower cost than with SCSI, but most ATA RAID controllers lack a dedicated buffer or high-performance XOR hardware for parity calculation.
For example, by including computed check bits, ECC memory is capable of detecting and correcting single-bit errors within each memory word, while RAID 1 combines two hard disk drives (HDDs) into a logical storage unit that allows stored data to survive a complete failure of one drive.
RAID stands for redundant array of independent disks (or, formerly, redundant array of inexpensive disks). RAID levels may refer to: Standard RAID levels , all the RAID configurations defined in the Common RAID Disk Drive Format standard, which is maintained by the Storage Networking Industry Association
A parity drive is a hard drive used in a RAID array to provide fault tolerance. For example, RAID 3 uses a parity drive to create a system that is both fault tolerant and, because of data striping, fast. [1] Basically, a single data bit is added to the end of a data block to ensure the number of bits in the message is either odd or even. [2]