Redundant array of independent disks (RAID) is a data protection method for storing the same data on multiple hard disks to increase performance and fault tolerance. When you use RAID data storage, the loss of any single disk won't interfere with users' ability to access the data stored on the failed disk.
RAID data storage appears to the operating system to be a single logical hard disk. RAID employs the technique of disk striping, which involves partitioning each drive's storage space into units ranging from a sector (512 bytes) up to several megabytes. The stripes of all the disks are interleaved and addressed in order.
In our quiz on RAID data storage, learn about the most important RAID storage terms, what they mean, and why they're important. Take our quiz, and if you haven't done as well as you've hoped, read our primer on RAID storage systems and download our free RAID level comparison chart.
RAID DATA STORAGE FOR BEGINNERS: START THE QUIZ
1. This is the process of dividing a chunk of data into separate blocks, and spreading the data blocks across several partitions on different hard disks.
2. This is a technique of checking to see if your data has been lost or written over when it's moved from one destination to another, or when it's being transmitted between computers.
3. Products in this class include Atrato Inc.'s Velocity 1000, EMC Corp.'s Atmos, IBM Corp.'s XIV Storage System, Xiotech Corp.'s ISE and others.These types of products were created to provide redundancy and data protection in disk arrays that don't use traditional parity RAID and rebuild approaches.
4. This technique is used to increase fault tolerance. It is an implementation of RAID across nodes instead of across disk arrays. It can provide fully automated data recovery in a local-area network or wide-area network even if multiple nodes fail.
5. This term describes a computer system or component that's been designed so if a component fails, a backup component can immediately take its place with no loss of service.
6. Storage networks must partition their physical disks into logical entities so that host servers can access storage area network storage. This term can be used to refer to an entire physical disk, or a subset of a larger physical disk or disk volume.
7. This RAID level combines striping (RAID 0) with independent data disks with distributed parity (RAID 5). It is best used for applications that need high reliability, and that need to handle high request rates and high data transfer rates.
8. This is a method protecting against multiple storage drive failures by creating two sets of parity data on an array of hard disks.
9. This acronym refers to computer hard disks that don't have a RAID system in place to increase fault tolerance and improve data access performance.
10. This is a variation of disk mirroring in which each multiple storage disk has its own SCSI controller. It provides data protection in case of disk failure, because data is constantly updated to both disks. But because the separate disks rely upon a common controller, access to both copies of data is threatened if the controller fails.
This was first published in September 2010