RAID level clarity: raid 3/4/5?

Im going to build a new system in the near future and trying to figure out how I want to handle my storage. I've read through all the different forms of RAID and heres what i have come up with for my future plans.

The drives I want to use:

2x 74Gb Raptors

1x 320 Seagate 16mb sata II

My plan would be to configure the two raptors into raid 0, and then use a 150gb partition from the seagate to back it up. So just to clarify....this would be raid 4 right?

The whole idea would be to get the advantages of raid 0 with the reliablility of Raid 1, but only needing to buy one parity/backup disk.

Im just wondering.....is my setup considered Raid 41 (4+1), would this even be possible? A little insight would be appreciated.[/url]

Well.. kinda. Usually RAID controllers only work with the same kind/size of disk. Your 2 - 74GB drives should work great with RAID 0. For backing up purposes, you would probably have to just set up a script to back up the disk to the other disk.

It's kind of like what I have on one of my conputers. I have 2 - 300GB drives running in RAID 1 for storage. My webserver runs off a 20GB drive and once a week a little batch file runs the DOS version of PKZIP to back up that drive to the 300GB cluster.

lucassix is correct on the hard drive size. Since you are using 74gb drives, if you RAID them your 320gb drive will only be seen as a 74gb drive rendering the rest of the drive useless.

For reference's sake - here's the "TechWeb.com" definition of RAID levels and their benefits:

RAID 0 - Speed
Level 0 is disk striping only, which interleaves data across multiple disks for better performance. It does not provide safeguards against failure. RAID 0 is widely used in gaming machines for higher speed.

RAID 1 - Fault Tolerance
Uses disk mirroring, which provides 100% duplication of data. Offers highest reliability, but doubles storage cost. RAID 1 is widely used in business applications.

RAID 2 - Speed
Bits (rather than bytes or groups of bytes) are interleaved across multiple disks. The Connection Machine used this technique, but this is a rare method.

RAID 3 - Speed and Fault Tolerance
Data are striped across three or more drives. Used to achieve the highest data transfer, because all drives operate in parallel. Parity bits are stored on separate, dedicated drives.

RAID 4 - Speed and Fault Tolerance
Similar to Level 3, but manages disks independently rather than in unison. Not often used.

RAID 5 - Speed and Fault Tolerance
Data are striped across three or more drives for performance, and parity bits are used for fault tolerance. The parity bits from two drives are stored on a third drive and are interspersed with user data. RAID 5 is widely used on servers to provide speed and fault tolerance.

RAID 6 - Speed and Fault Tolerance
Highest reliability, but not widely used. Similar to RAID 5, but performs two different parity computations or the same computation on overlapping subsets of the data.

RAID 10 - Speed and Fault Tolerance
A combination of RAID 1 and RAID 0 combined. Raid 0 is used for performance, and RAID 1 is used for fault tolerance.

actually, for raid 0, the configuration for the disks does not depend on the exact drive, but on the smallest drive. Raid 0 can be set up stiped with like a 100gb hdd and a 120, but u can only use 100 on the 120. u can still set it up. (just realized thats what grinch said.) But in all reality, the idea would be a strange version of raid 0 + 1. The whole idea was i could split the 320 into two partitions and use one for the raid array. so the backup for the raid 1 section would be 150, and the rest would be used just as extra storage. This is the best diagram i could make:

just realized, the idea of running a normal hard drive in raid 1 with two raptors would totaly nullify the idea of running the raps. in 0 anywyas, the double write would slow down bc of the seagate, therefore ruining the idea of the performance of raid 0 raptors

I do not use more raid 0. Almost all the data if not for a recovery lab called Onretrieval I I recover all lost...


One of the disks had failure physics. That is why I stayed had no access to the raid.

Now I use a raid 5. No problems.

Best regards.