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What is RAID?

G

Groovsonic

macrumors regular
Original poster
Oct 4, 2002
209
0
Near Chicago, Illinois
Hi!
Dumb question: What is RAID? I know it has something to do with multiple drives, and I think splitting up data between the drives, but what is the purpose? Is it faster than having data stored on a single drive, or is it slower? Any information would be much appreciated.

Thanks
 
RAID is an acronym for Redundant Array of Inexpensive (or Independent) Disks. A RAID array is a collection of drives which collectively act as a single storage system, which can tolerate the failure of a drive without losing data, and which can operate independently of each other.

more information can be www.adaptec.com/technology/whitepapers/raid.html+raid+explanation&hl=en&ie=UTF-8]found here[/URL] on the different levels of RAID...
 
Thanks eyelikeart. Although the link was apparently broken, I basically traced your steps to find the infromation. It was interesting.

Does anyone know how much faster accessing information would be with say a 3 or 4 drive raid than a single dirve? I want to know if it is worth investing in for my Music recording and video editing.

Thanks
 
Your speed will be reduced, as 1/3 of all writing (in a 3 drive RAID) would be redundant and spread across the other two drives.- Simplistic and not completely correct, but close enough. It also depends on how your accessing your RAID drive. A NAS (Network Attached Storage- a kind of RAID) will be significantly slower because of the CAT5 bottleneck, a fiber line would be faster, SCSI2 still faster, etc...)
 
Originally posted by Groovsonic
Thanks eyelikeart. Although the link was apparently broken, I basically traced your steps to find the infromation. It was interesting.

Does anyone know how much faster accessing information would be with say a 3 or 4 drive raid than a single dirve? I want to know if it is worth investing in for my Music recording and video editing.

Thanks
Click to expand...

I don't think it will speed up your audio editing, but for video it might under certain conditions. If you are editing DV you will see no improvement when using a RAID (current 7200RPM HDDs are more than fast enough to handle DV). If you are editing uncompressed video... well... if you were editing uncompressed video you'd already be using a RAID. ;)



Lethal
 
Originally posted by Eniregnat
Your speed will be reduced, as 1/3 of all writing (in a 3 drive RAID) would be redundant and spread across the other two drives
Click to expand...

Reallly? I must have misunderstood the idea. I thought it could be significantly faster because you are spreading data out over multiple drives and since all of the drives can be running at once, data can be pulled back faster. Is the only purpose of RAID for data protection?
 
Originally posted by LethalWolfe
I don't think it will speed up your audio editing, but for video it might under certain conditions. If you are editing DV you will see no improvement when using a RAID (current 7200RPM HDDs are more than fast enough to handle DV). If you are editing uncompressed video... well... if you were editing uncompressed video you'd already be using a RAID. ;)
Lethal
Click to expand...

So then I should just invest in one good FW HD instead of a few because I will see little to no improvement. Thanks for the info.
 
Originally posted by Groovsonic
So then I should just invest in one good FW HD instead of a few because I will see little to no improvement. Thanks for the info.
Click to expand...

Get a Firewire drive that uses the Oxford 911 chipset (if the drive uses it they'll advertise that fact) and you will be good to go for all yer DV storage needs. ;)


Lethal
 
My understanding is that RAID doesn't spread data over multiple drives, it stores *the same* date across multiple drives. It can basically be used as an instant backup. When you save a document, it gets saved to all the drives that are linked. It's used more to backup stuff in case one drive fails.
 
Originally posted by LimeLite
My understanding is that RAID doesn't spread data over multiple drives, it stores *the same* date across multiple drives. It can basically be used as an instant backup. When you save a document, it gets saved to all the drives that are linked. It's used more to backup stuff in case one drive fails.
Click to expand...
it can be. data can also be 'striped' or be split over multiple drives as one virtual volume.

here's a brief description of the different types of RAID (levels) and what they do.
 
I believe it all depends on what type of RAID you setup, while it is commonly used in servers for back up it is also used in a striping fashion. So your data is written to 2 drives at the same time. So basically if you d/l an Mp3 to a raid 0 (someone correct me if i'm wrong) configuration it will write half the data to one drive and half to another. I'm 99% sure this speeds things up a little (write and access time). The down fall is if one drive goes...bye bye data.
 
Originally posted by destroyboredom
I believe it all depends on what type of RAID you setup, while it is commonly used in servers for back up it is also used in a striping fashion. So your data is written to 2 drives at the same time. So basically if you d/l an Mp3 to a raid 0 (someone correct me if i'm wrong) configuration it will write half the data to one drive and half to another. I'm 99% sure this speeds things up a little (write and access time). The down fall is if one drive goes...bye bye data.
Click to expand...

-destroyboredom

You're describing what sounds like RAID Lev. 0 - technically not RAID, as there's no 'R' (redundancy) in the array.

That link above is one of the best, most concise table of RAID levels I've seen. I'm so scraping that.
 
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