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What are Disk Arrays?

R. Kayne
R. Kayne

Disk arrays are storage systems that link multiple physical hard drives into one large drive for advanced data control and security. They have several advantages over traditional single-disk systems.

A hard disk, while being the vital center of any computer system, is also its weakest link. It is the only critical device of a computer system that is not electronic, but relies on intricate moving mechanical parts that often fail. When this happens, data is irretrievable and unless a backup system has been employed, the user is out of luck. This is where disk arrays make a difference.

These systems incorporate controls and a structure that pre-empts disaster. The most common disk array technology is RAID (Redundant Array of Independent Disks). RAID utilizes arrays in a number of optional configurations that benefit the user.

A traditional hard drive is any computer’s weakest link because it relies on moving mechanical parts.
A traditional hard drive is any computer’s weakest link because it relies on moving mechanical parts.

One advantage of RAID disk arrays is redundancy of data writes so that if a file is damaged or stored in a bad cluster or disk, it can be instantly and transparently replaced from another disk in the array. RAID also allows hot-swapping of bad disks and increased flexibility in scalable storage. Performance is also enhanced through a process called "striping."

There are many varieties of RAID, and though designed primarily for servers, disk arrays have become increasingly popular among individuals because of their many benefits. RAID is particularly suited for gamers and multimedia applications.

RAID controllers, built into motherboards, must set parameters for interacting with disk arrays. The controller sets the performance parameter to match the slowest disk. If it were to use the fastest disk as the benchmark, data would be lost when written to disks that cannot support that speed. For this reason, all disks in the array should be the same brand, speed, size and model for optimal performance. A mix of capacities, speeds and types of disks will negatively impact performance. The best drives for disk arrays are SATA (Serial ATA) RAID drives. These drives are optimized for RAID use and, being SATA, are hot-swappable.

Using disk arrays can provide peace of mind while improving data security and performance. Motherboards with built-in RAID controllers support certain types of RAID. For example, an older or inexpensive motherboard might only support RAID 0 and RAID 1, while a newer or more expensive board might support RAID 1 through RAID 5. Be sure to get a motherboard or third party RAID controller that supports the RAID configuration you require.

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Discussion Comments


@kangaBurg – Your brother knows his stuff. Since he can install a RAID 0, why doesn’t he go ahead and put a SATA disk array of three drives in your PC? That would be better than your current setup.

SATA drives can transfer up to 6 gigabits of data each second. Doing a RAID with three of those will increase your computer’s performance even more. You also won’t have to do any backups, because the RAID configuration will keep your data safe.


@smartypantz – Thanks for the explanation. I have a RAID 0 storage array with two hard drives, but I never knew how it worked.

My brother set it up for me because I play a lot of PC games and the graphics slowed my computer down. After he did some other stuff to my PC, he added the array too, and it made my computer much faster.

He said my computer can read both hard drives at the same time, and that makes it faster. I still have to back up my files, though, because RAID 0 isn’t made for file security. That’s what my brother says, anyway.


I’m studying computer networking in college, so I want to explain what “striping” is, since the article only mentions it briefly.

A storage disk array is two or more hard drives working as one. How do they do that? Well, every file is made up of tiny bits of data. Disk arrays split the data up evenly across all the hard drives in the array. The splitting up of data is called “striping”. Special software is used to do this.

In most cases, after the data is striped, if one hard drive fails, special code on the other drives makes it possible to recreate the data that was on the faulty drive.

For really big systems, like MMORPG servers, data can be striped across entire arrays, instead of just across disks. That makes for a really secure database.

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    • A traditional hard drive is any computer’s weakest link because it relies on moving mechanical parts.
      By: meepoohyaphoto
      A traditional hard drive is any computer’s weakest link because it relies on moving mechanical parts.