Please explain Raid 0,1.... etc.

[Inikay]

Hi!

I never installed SATA drives. I only installed ata drives in my computers, but quite frankly don't know what's this Raid stuff... Is it only for SATA, or for all types of drives? And do optical drives have anything to do with this?

Can anybody explain how do you change these settings and what are they for, please?

Thanks,

Inikay.

 

[Baked]

Something about RAID here and here. RAID involves 2 or more hard drives (or floppy drive) and has nothing to do with optical drives. You'll need a controller, software or hardware, that supports RAID to set things up.

 

[techwanabe]

More than you ever wanted to know:

Short for Redundant Array of Independent (or Inexpensive) Disks, a category of disk drives that employ two or more drives in combination for fault tolerance and performance. RAID disk drives are used frequently on servers but aren't generally necessary for personal computers.

Level 0 -- Striped Disk Array without Fault Tolerance: Provides data striping (spreading out blocks of each file across multiple disk drives) but no redundancy. This improves performance but does not deliver fault tolerance. If one drive fails then all data in the array is lost.
Level 1 -- Mirroring and Duplexing: Provides disk mirroring. Level 1 provides twice the read transaction rate of single disks and the same write transaction rate as single disks.
Level 2 -- Error-Correcting Coding: Not a typical implementation and rarely used, Level 2 stripes data at the bit level rather than the block level.
Level 3 -- Bit-Interleaved Parity: Provides byte-level striping with a dedicated parity disk. Level 3, which cannot service simultaneous multiple requests, also is rarely used.
Level 4 -- Dedicated Parity Drive: A commonly used implementation of RAID, Level 4 provides block-level striping (like Level 0) with a parity disk. If a data disk fails, the parity data is used to create a replacement disk. A disadvantage to Level 4 is that the parity disk can create write bottlenecks.
Level 5 -- Block Interleaved Distributed Parity: Provides data striping at the byte level and also stripe error correction information. This results in excellent performance and good fault tolerance. Level 5 is one of the most popular implementations of RAID.
Level 6 -- Independent Data Disks with Double Parity: Provides block-level striping with parity data distributed across all disks.
Level 0+1 ? A Mirror of Stripes: Not one of the original RAID levels, two RAID 0 stripes are created, and a RAID 1 mirror is created over them. Used for both replicating and sharing data among disks.
Level 10 ? A Stripe of Mirrors: Not one of the original RAID levels, multiple RAID 1 mirrors are created, and a RAID 0 stripe is created over these.

In my MCSE classes, my instructor, an older seasoned fellow, stated that it stands for Redundant Array of Inexpensive Disks (not Redunant Array of Independant Disks as popularized recently)

RAID 0,1 and 5 are the most commonly used, but 1 and 5 are used in businesses for fault tolerance.

 

[Inikay]

Thanks! got it. So, I guess I don't need this for my home PC... I just install the 2 Hard drives (160 and 80GB) and use them separately, no?

Inikay.

 

[topslop1]

Yep - with raid you normally want two identical drives anyways.

 

[techwanabe]

Originally posted by: topslop1
Yep - with raid you normally want two identical drives anyways.

Normally yes, but from what I learned, you can use two unequally sized drives. For example with RAID 5 you need three drives (2 striped sets and 1 parity) for fault tolerance and some speed advantage. But if one of those three drives were bigger, the stripe set volume on the bigger drive would have to equal the size of the smaller drive. I think with dynamic disks, you might be able to use the remaining space on the bigger drive. But all this might be academic.