RAID what is it and why do I need it?

  • Thread starter I6-4-eva
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I6-4-eva

I6-4-eva

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United States
Nor. California
Someone hold me by the hand and draw me cute pictures of how RAID works.

Seriously I have no clue... I would google it but I'm lazy.

My mobo is an ABIT AN8 Ultra and on the piece paper it says something about SATA 150 RAID 0/1/0+1 JBOD and SATA 3G.

I'll be using it for games,watching dvds,p2p,stealing music,school work.. stuff like that.
 
As much as I know,RAID in computers mean connecting few hard drives,and using a RAID controller,the computer will recognise those hard drives like a one big hard drive.
i.e. Connect 3 150gb hard drives into a RAID to create a 450 gb hard drive.

RAID 0,1 and 0+1 are AFAIK the 3 possible ways to create a RAID,they all have their prons and cons.

What is the difference and how to do it,I don't know.
Recently I read about it in a computer magazine,but this is all I could remember now.

EDIT:I started typing this post around 13:23 , and at that time I did not see that someone else already gave the link to the explanation.
 
Yep, that Wikipedia entry is bang on the money.

When it comes to specifying a RAID system, you have to consider a triangle. At one point is the total capacity of the system. At another is the number of disks that you can tolerate failing. And the third is the cost.

You can calculate the capacity of the array thus:

Number of disks = n
Capacity of disks (assumes all the same, or use size of smallest disk) = c

RAID 0: c * n)
RAID 1: c * (n / 2)
RAID 0+1: c * (n / 2)
RAID 5: c * (n - 1)
RAID 6: c * (n - 2)
RAID 10: c * ((n - 1) / 2)

One area that the Wikipedia entry misses out is that modern controllers can do RAID 0+1 on two disks, and that this will typically include your ASUS board. This is done by striping the disks, and then mirroring them.

It doesn't work like this, but it's a convenient aide memoire: Imagine two rectangles next to each other. Divide each one in half horizontally. This gives you four squares. Each file you write will be half in the upper square, and half in the lower square, and mirrored with its corresponding square on the opposite disk. The beauty of this is that both drives can write the file at the same time. One disk writes the upper half, and the other disk writes the lower half. Then, when they've completed, each disk updates its mirror of the other. This allows a RAID 0+1 disk to operate with exceptional performance whilst maintaining data integrity and redundancy.
 
Which ones speed up the process of data retreival?

I know that one of them gives you the same capacity as one of the disks but can retrieve data twice as fast. That would be the one i'd use: Two 74gb Raptors :)
 
donbenni
Which ones speed up the process of data retreival?

I know that one of them gives you the same capacity as one of the disks but can retrieve data twice as fast. That would be the one i'd use: Two 74gb Raptors :)
Click to expand...

Raid 0 will (theoretically) double your reading and writing speed..

Raid 1 will maintain the same speed as one disk while keeping all data redundant..
 
Define ordinary.

If you have lots of video then yes.
If you have lots of games then yes.
If you have lots of images yes.
If it's a server computer then yes.
 
Young_Warrior
does the ordinary user ever require raid?
Click to expand...

Ordinary and ordinary. I may be a little to the geeky side and have used Raid 0 since I first got a Mobo that supported it. Maybe 4 years ago - I love the performance I get from it - so if you have the opportunity, I say go for it...

Buyer beware though - IF you decide to use Raid 0, please remember to keep your disk cooling above average, and do a back up every once in a while - One dead disk will destroy all your data...
 
What would be the best RAID for a gaming/workstation PC? RAID 10 or 0+1? I know there are cost differences, but which is generally better performance wise?
 
Anyone care to give me an answer or some interesting hypotheticals?
 
Omnis
What would be the best RAID for a gaming/workstation PC? RAID 10 or 0+1? I know there are cost differences, but which is generally better performance wise?
Click to expand...

Just go with RAID 0 that's what i'm using right now. 64k stripe size.
 
Omnis
That doesn't answer my question, though.
Click to expand...
Raid 0 will give you the best performance but won't offer redundancy (ie, protection from a drive failing). Raid 0+1 will offer the same performance and redundancy, but as far as I'm aware, it requires twice the drive space...

For gaming, the only benefit is that the 60 second load times will drop to 30 seconds. Other than that, the performance benefit will only be seen if you constantly handle massive files
 
GilesGuthrie
Yep, that Wikipedia entry is bang on the money.

When it comes to specifying a RAID system, you have to consider a triangle. At one point is the total capacity of the system. At another is the number of disks that you can tolerate failing. And the third is the cost.

You can calculate the capacity of the array thus:

Number of disks = n
Capacity of disks (assumes all the same, or use size of smallest disk) = c

RAID 0: c * n)
RAID 1: c * (n / 2)
RAID 0+1: c * (n / 2)
RAID 5: c * (n - 1)
RAID 6: c * (n - 2)
RAID 10: c * ((n - 1) / 2)

One area that the Wikipedia entry misses out is that modern controllers can do RAID 0+1 on two disks, and that this will typically include your ASUS board. This is done by striping the disks, and then mirroring them.

It doesn't work like this, but it's a convenient aide memoire: Imagine two rectangles next to each other. Divide each one in half horizontally. This gives you four squares. Each file you write will be half in the upper square, and half in the lower square, and mirrored with its corresponding square on the opposite disk. The beauty of this is that both drives can write the file at the same time. One disk writes the upper half, and the other disk writes the lower half. Then, when they've completed, each disk updates its mirror of the other. This allows a RAID 0+1 disk to operate with exceptional performance whilst maintaining data integrity and redundancy.
Click to expand...

You forgot RAID 3. Of course, that's a fairly recent release. It's basically able to save two hdd failures instead of just one.
 

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