For non-technical people, the first thing that comes to mind when they think about a raid is the pandemonium that ensues following an unexpected attack. However, when it comes to your IT, RAID has a different, less aggressive connotation. RAID is an acronym for Redundant Array of Independent Disks, a method of storing the same data in different places on various hard disks to ensure redundancy in the case of a drive failure.
In 1987, the term RAID was coined by David Patterson, Randy Katz and Garth A. Gibson. In their 1988 technical report, "A Case for Redundant Arrays of Inexpensive Disks (RAID),” the trio claimed that an array of inexpensive drives could outperform the top disk drives of the time, and that by utilizing redundancy, a RAID array could be more reliable than any one disk drive alone. So far as benefits are concerned, we’ve barely scratched the surface.
How it works
RAID places data on multiple disks and allows storage operations to evenly overlap, improving performance and ensuring data integrity should a disk fail. RAID configurations also employ disk striping, a technique that mirrors data over multiple disk drives, allowing you to read or write to more than one disk at the same time.
When distributed, the data gets divided into segments, which are spread across disks in the array. This increases both the capacity and the speed of your storage system because what is presented as a single drive is actually several hardware drives tackling workloads individually.
Depending on how you want to balance performance and fault tolerance, RAID devices have varying structures and are comprised of different levels. Each level is responsible for a specific task and has a unique advantage. Here are the benefits of the most used RAID levels:
- RAID 0: In this level, an individual file can be read from multiple disks. This improves speed and storage capacity because this level splits data across any number of disks, allowing for higher throughput. This level is referred to as striping and allows for increased performance. However, it doesn’t provide redundancy and fault tolerance since it doesn’t duplicate data. RAID 0 is normally implemented for caching live streams and other files where speed is key, not reliability or data loss.
- RAID 1: Unlike RAID 0, this level’s primary function is to provide redundancy and does so by writing and reading identical data into pairs of drives, a process known as data mirroring. If any of the disks fail, the system can still access data from the remaining disks. After replacing the broken disk, data is automatically copied to it from the functioning disks to rebuild the array. RAID 1 is the easiest way to create failover storage.
- RAID 5: Although this levels also stripes data blocks across multiple disks like RAID 0, RAID 5 is different in that it aids in data recovery by storing small amounts of data that accurately describes larger amounts of data. If any of the disks in the array were to fail, data can be recreated from the remaining distributed data. This ”parity” information takes up around one-third of the available disk capacity.
- RAID 6: RAID 6 is similar to RAID 5, but it provides increased performance and reliability because it stores an additional parity block. This means that it’s possible for two drives to fail at once without disrupting the array.
- RAID 10: This level possesses the striping of RAID 0 with the mirroring of RAID 1. Basically, RAID 10 is a consolidation of enhanced performance and redundancy, making it ideal for environments where both high-performance and security are needed.
Backup or back up?
Warning: Just because certain RAID levels provide data redundancy, doesn’t mean you should consider them be-all-end-all backups for your most critical files. RAID protects you against hardware failure -- not against errors, file corruption, or malicious activity. RAID can be a great way to recover from hardware failure as well as optimize network-attached storage (NAS) and server performance. But don’t forget that it’s only part of an overall data backup and disaster recovery solution.
Choosing the appropriate RAID levels for your server depends heavily on intended usage and the goals you wish to achieve with it. Not to mention budgetary and hardware constraints, both of which have a significant impact during the decision making process. We at Complete Technology understand that finding the right IT resources can be difficult, but with proper guidance, it doesn’t have to be. Just call us or send us a message.