Ok, i don't know anything about raid. But i want to set one up in my computer. All i was wondering, i currently have a 20 maxtor, 80 seagate, and another 80 seagate coming. I was planning on just using the two 80 seagates in my raid setup. But i had an idea and thought i would ask around. I know you have to have each drive in a raid setup the same size, so could you partition the 80 gig drives so that they 8 20 gig drives and then use all of the hard drives in a raid setup??

Raid is a data integrity system, to protect your data, I do not think that this is what your looking for however if you want please read on.

Raid does not work at the level at which your are talking about, to answer your question... this is how raid setups are implemented, (please keep in mind most mobo's with onboard raid systems only support raid 0, 1 and 0+1)

[please do not give credit for below I didn't write it, i started to write my own but decided it would take to long, why reinvent the wheel?]

RAID 1 - Worried that your hard drive may crash and take with it everything you've diligently forgotten to back up? RAID 1 is for you. RAID 1, otherwise known as mirroring, duplicates the contents of your primary drive onto an auxiliary drive to guard against physical drive failure. If one or the other crashes, you have a perfect backup. However, RAID 1 won't protect you against viruses or other threats to the integrity of data on your hard drive; RAID 1 is useful only for extending the Mean Time Between Failure (MTBF) of your storage setup. In the event of a drive crash, just replace the damaged disk with a new drive, and the RAID card will rebuild the mirrored array.
Despite the fact RAID 1 uses two physical hard drives, the operating system only sees one logical drive. Since data on one drive is duplicated on the other, a two-disk RAID 1 array's storage capacity will only be equal to the storage capacity of a single disk.


RAID 0 - RAID 0 eschews the redundancy of mirroring in favor of striping, which spreads one logical drive over multiple physical hard drives. Blocks written to and read from the array are spread over multiple disks, which improves performance, but greatly reduces reliability. A striped logical drive is vulnerable to the failure of any one of its physical hard drives. If, for example, you had a two-drive RAID 0 array, your MTBF is cut in half since you have twice the exposure to drive failure. A failure of any drive in a RAID 0 array will kill the array completely and take with it all the data on the logical drive.
Though striping kills redundancy, it at least maximizes the storage capacity of the physical drives in the array. Since a RAID 0 array's logical drive is spread over each physical drive, the total storage capacity of the array is the sum of the physical drives' storage capacities.

Just for kicks, we'll be looking at two-drive and four-drive RAID 0 arrays in this comparison to give you an idea how RAID 0 performance scales with additional drives.


RAID 10/0+1 - RAID 10 and 0+1 are similar in that they attempt to achieve better performance and redundancy by combining RAID 0 and RAID 1 arrays. However, RAID 10 and 0+1 go about combining mirroring and striping a little differently. RAID 10 is a striped set of mirrored arrays, while RAID 0+1 is a mirrored pair of striped arrays. Striped mirrors versus mirrored stripes. Got it?
Because RAID 10 and 0+1 both combine mirroring and striping, they share the same storage capacity characteristics. With either a RAID 10 or 0+1 array, the total storage capacity of the array will be equal to half of the sum of the storage capacity all the drives. Both keep a mirrored duplicate of their respective arrays' logical drives, so only half of the drives' total storage is available.

RAID 10 and 0+1 arrays share the same storage capacity, and they're both sufficiently redundant to guard against a single drive failure, but after a single drive failure, RAID 0+1 is vulnerable. If a single drive in a RAID 0+1 array fails, you lose your mirror and are left with a striped RAID 0 array. That striped RAID 0 array is going to have a lower MTBF than a single drive, so you'd better get a replacement drive in a hurry. A RAID 10 array is actually capable of withstanding multiple drive failures under the right circumstances. RAID 10 can survive a second failure if it occurs in a different mirror group than the first failed drive. However, if two drives fail within the same mirror group, all you're left with is half of a striped array, which is useless.

Technically, two drives could fail in a RAID 0+1 array without killing you if both failures were limited to the same stripe group. However, since a RAID 0+1 array reverts to a single RAID 0 stripe in the event of a single drive failure, the drive that could be sacrificed for a second failure isn't being used anyway, so there's no reason for it to fail.

[[end of stealing words]

ok, so now you have idea of what you can do, with what you have. raid really is meant for servers except in the case of raid 0 if by the way your board doesnÂ’t support raid and you were planning on wasting some money on a raid adapter these other levels of raid come into play, (except that IÂ’m not sure if you can implement them in an IDE situation you might have to be running a SCSI setup) you can see the other levels of raid >here

Quote: Originally posted by jhoop2002 so could you partition the 80 gig drives so that they 8 20 gig drives and then use all of the hard drives in a raid setup??

No.

Here's some of my RAID 101.

RAID - Redundant Array of Independant Disks.
There are several types of RAID. Here are the most important. The numbers are blocks of data.

RAID 0: Striping. Two disks where the data is spread across the disks so that every second block is on one of the disks.
+ Improves speed.
- Unsafe.

RAID 1: Mirroring. Both disks contain the same data.
+ Safe.
- Wastes half the space.

RAID 3: A third drive stored parity information (XOR). If one disk dies, the data can be rebuilt using this information. One disk is the parity disk. Can be used for more than 3 disks as well.
+ Safe.
- Requires complicated controller.

RAID 5: Every n:th block in an array of n disks is a parity block. If one disk dies data can be saved. Can be used for more than 3 drives.
+ Safe.
- Requires complicated controller.

RAID configurations can sometimes be combined if the controller alows it. For example, RAID 50, RAID 10 and so on. RAID 50 requires at least 6 drives.

All RAID configurations require the disks to be of the same size. If they are not the size of the array is based on the size of the smallest drive.

If you don't have drives with the same size and want to run them as JBOD (Just a Bunch Of Disks). A bit like RAID 0 except it's not faster than a single drive.

Lot's of good info in this thread. This thread will be earmarked for future reference. Good job.

What i was looking for was a way to at least use the two 80 seagates and gain some extra performance. What i don't understand is when you say that when you run RAID 0 that you put your data at a higher risk. While i understand that now you are depending on two drives (so you risk of failure goes up), and if one fails your screwed, its almost the same as I am right now, depending on the two drives. If my boot drive fails I am screwed and if my other drive fails I am screwed. So with that in mind i don't think running raid really increases my chance of failure all that much. So my question is, does running a raid setup decrease the life of a hard drive, and since all i want is performance, what is the best setup to run?

My board supports RAID 0, RAID 1 RAID 0+1.

EDIT:: So, RAID 0 is the "fastest" raid setup for IDE drives?? and i guess i still don't understand how RAID 0 is unsafe.

There is no redundancy, no backup of your data. If one drive fails, the data on both drives are worthless. Running two drives in RAID 0 doubles your chances of a hardware failure. That being said, I run RAID 0 but image them on a regular basis.

I also was planning on running a RAID 0 array (after I get some money for a second HDD). Do both hard drives have to be the same speed? For example could one set up an array of an ATA 133 drive and a SATA drive? From what I have read it sounds like it would work with different speeds but the overall speed would be equal to that of the lowest speed drives.

I couldn't tell you about mixing SATA and ATA drives. The SATA technology is still so new that I have little experience or knowledge of them.

But you are correct in your assumption that the array would configure to your slowest drive. But, to minimize any data corruption, the closer matched the drives the better. I would not run a 5400 and a 7200 in a RAID 0 configuration.

The same holds true for drive capacity, RAID 0 will result in double the capacity of your lowest capacity drive. If you want to run RAID 0, I would recommend getting a matching pair of good performing hard drives to start with. After all, you are looking for performance if you go RAID 0.

As i was sitting in my english class for the last two hours, i had an idea on how to keep my data if one drive did fail. Since i already have a 20 gig maxtor that should last for awhile, what i was thinking about doing was running two 80 gig seagate drives in a RAID 0 and then having another drive (20 gig Maxtor) just sitting there, so any important data can be backuped to that drive on a daily basis and then burned to a CD-RW weekly.

Hows that sound, it can be done right?

That's what I do hoop. I image my RAID to a backup drive. Saved my ass a few times. A 20 would probably hold 1 backup from a dual 80 setup, I would look at getting a spare 60 to hold a couple of full backups. It all depends on how much crap you load onto your RAID configuration.

The risk of failure isn't only dependant on a drive failing when it comes to RAID 0. This will also destroy the data beyond repair:

- Drive failure (like said)
- Mobo failure
- Flashing BIOS (only some boards, some versions)
- BIOS reset

If you run two single drives, one failing drive will only destroy data on that drive. In RAID 0 it destroys all the data on the array.

So the risk is signinficantly higher. But with a backup drive like you say, the "chances of survival" are greater. Just make sure it's big enough for all important data.

Quote: Originally posted by bigakita There is no redundancy, no backup of your data. If one drive fails, the data on both drives are worthless. Running two drives in RAID 0 doubles your chances of a hardware failure. That being said, I run RAID 0 but image them on a regular basis.

How do you figure the chances of your HD failure doubles? It doesnÂ’t, there is no disadvantage to raid 0 however its not a redundant system, (go figure they call it raid!)

The reason it doesnÂ’t double your chances of HD failure because even if you where to run one HD and it happened to crash it would be the same as running two, except that assuming only one of the drives crashed you would still be able to use the other one in a non raid instance. Really there is no disadvantage except if you were looking for data integrity.

Dr. Who - I am sorry friend, but you are missing the big picture. It is simple high school stats (probably elementary school stats these days!):

We all agree that if one drive fails in a RAID 0 array, it will wipe out the entire array.

If the risk of 1 hard drive failing and wiping out your data (in a non raid situation) is "x".

The chance of one HD failing and wiping out all your data in a RAID 0 array consisting of 2 HDD's would be "2x".

2x/x=2 Or rather twice the likelihood, or in turn, double the risk.

Pretty simple concept really. And undeniably true.

let not turn this into a math class, but i understand what you guys are talking about. As far as having a third drive that i can image a complete array to, i don't think i will do that. If one drive fails i will just replace it and reinstall everything and then move all my data that backedup back into the array.

I would honestly recommend a small raid0 array for loading apps or anything that requires an excessive amount of harddrive read/write activity.

My 3 10k rpm IBM SCSI 9.1 giggers = 27.3 gigs, more than sufficient to run any apps I might need as well as my baby sql server, and I can back it all up to a 28 gig partition on my 80 gig ide drive with room to spare on separate partition for file storage.

When you start talking about large raid0 arrays, it becomes problematic backing up all that data

I would suggest raid5 or single volume for file storage.

Just my personal thoughts on the subject, just make sure you dont boot off a raid5 or put your pagefile on the raid 5 *snicker*

yeah, that sounds like a good idea but i only got these three hard drives and i'm not buying any more until i have too.