Despite the popularity of c++ array when it comes to data storage and backup, many people are still a bit confused with some of the terms that are used in the discussion of these configurations. In this article, we’ll look at some of the most common RAID related terms and their definitions.
RAID is an acronym for Redundant Array of Independent Disks. Sometimes you’ll see it as Redundant Array of Inexpensive Disks. RAID technology combines two or more disk drives for improved data storage, retrieval, back-up and fault tolerance. It lets you store the same data in more than one place so that it can be recovered even if one or more of the original disk drives fails.
An array is the group of hard disk drives used in a RAID configuration.
Hard disk drive:
Abbreviated as HDD and also referred to as a drive, hard drive, disk or hard disk, a hard disk drive is the component of your computer where data is stored. The data is stored on a disk or platter and accessed by the read/write heads.
CDP stands for Continuous Data Protection and is designed to eliminate any chance for data loss due to hard drive failure.
The controller is an electronic device that organizes the structure of a RAID array. The controller connects to each individual disk in the system and allows them to communicate with the host system as if they were a single disk drive.
Redundancy refers to the fact that data stored in a RAID system is stored in more than one place at a time. This protects you against data loss to some extent since data that is lost due to the failure of one hard drive can usually be recovered from its place on another drive in the system.
A stripe is a small block of data that has been recorded in a RAID array. Striping is the process of dividing a block of data into small segments and distributing them across multiple drives within a RAID system.
Mirroring refers to storing identical copies of a string of data on two separate hard drives. There are two primary advantages of mirroring: you can recover the data from one drive if the other one fails, and you process more than one read request at a time and therefore access data more quickly than you could with a single drive.
Parity involves performing a logical operation on data as it is stored and then storing the result on a separate drives or on all of the drives in an array. This allows the original data to be reconstructed if any of the drives in a RAID configuration fail.
Striping with Parity:
Striping with parity adds fault tolerance to your system but reduces your storage capacity to some degree. Blocks of parity information are striped, or stored in smaller groups on each disk in the array.
Levels are different configurations within the concept of a RAID system. There are numerous RAID levels, some of which are commonly used, others are rare or obsolete.
Fault tolerance is the degree to which a RAID array can withstand disk drive failure within the array while still allowing you to access your data.
The amount of storage capacity use for stored information compared to the total storage capacity needed for the RAID level of your system. It’s expressed as the number of drives needed for the actual storage capacity compared to the number of drives needed to provide redundancy.
The host system is the computer system that is connected to the RAID array.
A hot spare is a hard drive connected to the array that is not being used, but is available to be brought on line if one of the other drives in the array fails.
The protection gap is the length of time between data backups.