Soldato
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Thanks guys.
Can somebody explain RAID to me please!
- Thread starter Cleisthenes
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At its most basic its a way of either increasing performance or fault tolerance. You can have both as well but it requires more than two drives.
In performance (RAID 0) mode you read and write to two or more drives at the same time.
In fault tolerance (RAID 1) mode you write the same information to both drives so if one fails the other is still going.
It can get much more complicated with more than two drives but that's beyond desktop use really.
In performance (RAID 0) mode you read and write to two or more drives at the same time.
In fault tolerance (RAID 1) mode you write the same information to both drives so if one fails the other is still going.
It can get much more complicated with more than two drives but that's beyond desktop use really.
A bit more specific question may get your more answers, what do you want to know about RAID - What is the different types? Pro's and con's? How to set it up? How to rebuild an array? etc.
I have no experience with any however have been doing a lot of reading up due to looking for a NAS box. Some basics though, the four most common ones are
RAID 0 - You need a minimum of 2 disks and data broken up and the bits are spread across the disks (striping). Advtantages of this is you get full disk storage and read and write speeds will increase over a single disk speed. Disadvantage is that if one disk fails you loose the lot as every file will be incomplete.
RAID1 - You need a minimum of 2 disks and all data is stored on both. Each disk will contain exactly the same data (mirroring). Advantages is that if 1 disk fails you have all you data on the other. Disadvantage read and write speed aren't that good. It also means that you need twice the amount of disk space as data you have ( 2 x 1Tb disk will only give you 1Tb of storage).
RAID5 - You need a minimum of 3 disks and data, the data is striped (split) across multiple disks while also storing parity data across the drives. Advantages is that gives some redundancy as if one drive fails you don't loose the data and also gives good read speed. Disadvantages is you loose a disks worth of space, ie 3 x 1Tb disks gives 2Tb total storage, 5 x 1Tb disks would give 4Tb storage. RAID5 write speeds aren't that good.
RAID10 - is actually RAID 1 + 0, so a minimum of 4 disks needed with the data being mirrored and striped. Advantages is that you have good speed and redundancy should 1 disk fail. Disadvantage, need 4 disks but only get 2 disks worth of storage.
There is also RAID2, RAID3 et al but they aren't so widely used so haven't detailed them. There are plenty of places which list details of RAID and go into a lot of detail about each one. Google is your friend.
I have no experience with any however have been doing a lot of reading up due to looking for a NAS box. Some basics though, the four most common ones are
RAID 0 - You need a minimum of 2 disks and data broken up and the bits are spread across the disks (striping). Advtantages of this is you get full disk storage and read and write speeds will increase over a single disk speed. Disadvantage is that if one disk fails you loose the lot as every file will be incomplete.
RAID1 - You need a minimum of 2 disks and all data is stored on both. Each disk will contain exactly the same data (mirroring). Advantages is that if 1 disk fails you have all you data on the other. Disadvantage read and write speed aren't that good. It also means that you need twice the amount of disk space as data you have ( 2 x 1Tb disk will only give you 1Tb of storage).
RAID5 - You need a minimum of 3 disks and data, the data is striped (split) across multiple disks while also storing parity data across the drives. Advantages is that gives some redundancy as if one drive fails you don't loose the data and also gives good read speed. Disadvantages is you loose a disks worth of space, ie 3 x 1Tb disks gives 2Tb total storage, 5 x 1Tb disks would give 4Tb storage. RAID5 write speeds aren't that good.
RAID10 - is actually RAID 1 + 0, so a minimum of 4 disks needed with the data being mirrored and striped. Advantages is that you have good speed and redundancy should 1 disk fail. Disadvantage, need 4 disks but only get 2 disks worth of storage.
There is also RAID2, RAID3 et al but they aren't so widely used so haven't detailed them. There are plenty of places which list details of RAID and go into a lot of detail about each one. Google is your friend.
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cool, thanks for the quick response. The water cooler picture intrigues me, would be cool if one of you could post it!
Redundant Array of Inexpensive Disks. Short explanation: It's a way of making disks work together to make them bigger/faster/more resilient to data loss.
It comes from the days when hard disks were small, slow and expensive, and you had to link them together if you wanted to make them work better.
It comes from the days when hard disks were small, slow and expensive, and you had to link them together if you wanted to make them work better.
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so in this day and age its only for the speed freak?
No, I use RAID1 for resilience, so if a drive fails, my system will still run while I'm getting a replacement (I've had it happen before).
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ahh sounds safe!! May have to invest in the distant future when i'm not so poor 
It really depends on why you want to move on from JBOD (Just a Bunch Of Disks). Ranking budget, write speed, read speed and data redundancy importance to you all effect choice of which RAID array to go for.
RAID can be useful for data redundancy as it protects against a disk failure but ultimately the disks will still be in a box (PC, Microserver, NAS box etc) and in one location so just because you use RAID doesn't mean you don't still need to back up important files.
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Most people don't make the distinction between redundancy and resilience. RAID was never meant to replace backups and they are for different things.
For instance, RAID isn't going to help you if you accidentally format your system disk.
I cannot stress this enough, RAID is NOT for backups. A lot of people make this basic mistake.
That was my point
as the R in RAID stands for redundant, I don't think using the term 'data redundancy' is wrong especially when I explained that a back up would still be needed. My post could have been more elequent had I used 'data resilience' and 'data redundancy' but I think I made the point clear enough.
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That was my point
Oh, I wasn't criticising or disagreeing, just expanding on the discussion points.
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interesting, this makes me feel massively behind on all things RAID!!! I will attempt to understand as much as I can haha
Is there anything in particular you want to do?
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potentially RAID 0 in the future, with 2 ssd's, but until I have that kind of disposable income it isn't going to happen! Although RAID 1 might be the more sensible choice. But no I haven't really got any thing in particular that I want to do as of now.
The problem with RAID 0 is that if one drive fails, you normally lose all data off both drives. You may find no speed benefit with SSDs, as they are so fast they can saturate the SATA interface by themselves, so two might not be any faster in RAID 0.
So all you could get is a larger single volume with no or very minimal increase in speed, and an increased risk of losing your data. In that situation I'd just have the two drives as separate volumes and re-arrange my data as necessary.
Decent motherboards have a raid controller. I setup raid 0 on my gaming machine, main reason was I filled my 180gb ssd so I bought another.
Don't be put off, yeah if one drive fails you lose all data but that can happen with a single drive too, you should always backup your data regardless.
Anyway you will see a performance increase with ssd's in raid. My win 8 boots before my monitor comes on, they are crazy fast. Pretty much doubled in speed, peaked over 1kMBps when I benched them.
Don't be put off, yeah if one drive fails you lose all data but that can happen with a single drive too, you should always backup your data regardless.
Anyway you will see a performance increase with ssd's in raid. My win 8 boots before my monitor comes on, they are crazy fast. Pretty much doubled in speed, peaked over 1kMBps when I benched them.