RAID: What Is It and Do I Need It?

[MDPS]

ATTENTION: This is my first take on a guide. I haven't seen this specific topic anywhere else on the forum, so I figured I might as well. If someone else has done this before me then I honestly must have looked over it.

 

Greetings!

So you're probably here because you want to set up a Server/NAS, or maybe just want an existing one to run more efficiently. If you've ever looked into this subject you'll probably have heard about RAID. This guide is to show you what RAID is, if you need it, and (if you do) which one to use.

 

RAID stands for Redundant Array of Inexpensive (or sometimes "Independent") Disks. In general, a RAID-enabled system uses two or more hard disks to improve the performance or provide some level of fault tolerance for a machine—typically a NAS or server. --- PCMag

In other words, you use RAID to get your storage configuration to work together better and (in some cases) provides a failsafe system incase an error occurs. There are many different levels of RAID, all meant for different (but for the most part similar) purposes, so for the sake of this guide I'll only cover the most common forms of RAID, and provide links to the others at the bottom.

 

RAID 0:

Also known as "Disk Striping", RAID 0 is meant to increase server performance. Instead of having your data written on a single disk, it writes it on multiple (using stripes, or a sort of bridge between the disks). This basically means that the work the computer does is handled by all disks included in the RAID, as appose to just one. This increases the speed of the included disks' I/O, making your disk R/W much faster. However, it has a drawback. As the data is shared among multiple disks, if one fails, then the data is comepletely lost altogether. Not recommended for OS storage. - A minimum of 2 disks are required for RAID 0.

 

RAID 1:

Also known as "Disk Mirroring", RAID 1 is meant for fault-tolerance. By "mirroring", or copying, all files on a disk to another whenever a change is made, it prevents data lossage if a disk fails, as it can recover data from the disk's "mirror". This does slow down performance a little and as it needs the space to copy, it cuts all disks included in the RAID's capacity in half. If you had 2 2TB disks, you now have a safer, but much smaller 2 1TB disks. Also note that no RAID is 100% foolproof, though they are pretty effective. - A minimum of 2 disks are required for RAID 0.

 

RAID 5:

This RAID is the most common for businesses and enterprises, but its a bit harder to explain. Look at the animated illistration to follow what I'm saying.

So essentially, RAID 5 is meant to be the go-between from 1 and 0. It grants a bit better performance boost than mirroring while still not sacrificing data safety. Basically, data and parity (automatically generated backed up data) are striped across three or more disks. If one fails, then saved data is copied from the failing disk's parity block (illustrated above), and moved through the stripes (data bridges) to another disk. In turn, rescuing any data that was at risk of being lost. Both the parity block generation and stripe transfer are seamless and automatic, and so the server system (and those using it) can continue to run unaffected. - A minimum of 3 disks are required for RAID 5.

 

RAID 6:

Pretty much identical to RAID 5, with the exception that it one more parity block, so you can have 2 disks fail before the system is compromised, as apposed to RAID 5's 1. - A minimum of 3 disks are required for RAID 6.

 

RAID 10:

Don't have a picture sorry. Enjoy this green text though!

RAID 10, also known as RAID 1+0, is appropriately named. It is basically a mix between RAIDs 1 and 0. It gives much better performance, but unfortunately requires more disks to run it. Generally used for larger corporations with much bigger storage servers. - A minimum of 4 disks are required for RAID 10/1+0.

So Those are the main RAID configurations.

There's also RAIDs 2, 3, 4, and 7 but they are mostly just modified versions of the above (which are the main RAIDs) and so I won't include them in this guide, but you can look them up at the links below.

These are considered "Standard" RAIDs, but there are also "Non-Standard" RAIDs which you can also look up in the links below.

Thanks for reading my guide!

 

LINKS:

Source 1: https://en.wikipedia.org/wiki/RAID

Source 2: http://www.pcmag.com/article2/0,2817,2370235,00.asp

 

RAID 2: https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_2

RAID 3: https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_3

RAID 4: https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_4

RAID 7: http://www.pcguide.com/ref/hdd/perf/raid/levels/singleLevel7-c.html ( NOTE: RAID 7 is not an open industry RAID, nor is it for consumer use. It has been trademarked by the Storage Computer Corporation)

 

Nonstandard RAIDs: https://en.wikipedia.org/wiki/Non-standard_RAID_levels

[Enderman]

or you can just watch this 5 minute video

[MDPS]

or you can just watch this 5 minute video

Thats only 1, 0, and 10. This guide goes indepth on 5 and 6, as well as provides links to the rest and non-standard RAIDs.

[Enderman]

Thats only 1, 0, and 10. This guide goes indepth on 5 and 6, as well as provides links to the rest and non-standard RAIDs.

here are the other kinds

but regular consumers mostly use 0 and 1 so this isnt really that important

[Ceatra]

Nice guide...

 

 

though I didn't read it all

[thekeemo]

Its what I use to get cockroach stampedes in my garage in Egypt...