IDE RAID with 3 or 4 drives....any faster?

[harkm]

Is anybody running IDE RAID with more than 2 drives? Do you notice a significant difference?

Mike

[This message has been edited by harkm (edited 09-07-2001).]

[daveleau]

In theory, the more drives the faster the disk access. I never got intobenching hdds, because I could never get a reliable app to do so. I did notice a significant increase with my RAId with 2 drives. With 3, I am not sure if the increased speed had to do with a freshly formatted drive, or the 3rd drive added to the array. It seemed to be negigible.
Dave

[BBA]

Yes...each drive in striping will increase speed.

The theoretical increase is each added drive will have an additive increase in speed.
IE: One drive=1X speed, two drives=2X speed. 3 drives = 3X speed, etc...

This does NOT take into account ide channel data saturation or device sharing, so depending on how fast each drive is compared to how fast the ide bus is, you may not get such a linear increase in speed. If you have ATA-100, a speed increase will pretty much hold true anyway.

If the drives are mirrored, speed will not increase but fault tolerance will.

[OC Guy]

In "theory" it should work.

[falcompsx]

problem with that theory is the imiitations of current IDE interfaces. you can only read/write to one drive at a time. so adding another drive will probably not help performance and will probably hurt it overall.

[JayMan]

Falcompsx, they are talking about a RAID 0 setup, By using a RAID controller in RAID 0 form u can "stripe" the data over 2 or more drives, so the data is written on all the drives at the same time, hence a faster speed. The following is taken out of my manual for my mobo (which has onboard Promise RAID controller)

RAID 0
For Capacity - The motherboard array will be as big as they smallest HDD in the array times however many HDDs are in the array. Any larger HDDs will simply be truncated. The truncated space on the biger HDDs will the be unusable.

For Sistained Data Transfers - A RAID 0 array consisting of two HDDs will transfer at about twice the speed of the slowest HDD in the array. A RAID 0 array consisting of four HDDs will transfer at about three times the speed of the slowest HDD in the array.

Therefore: 2 drives (RAID 0) = 2x slowest drive AND 4 drives (RAID 0) = 3x slowest drive.

So going by that u get the biggest increase from single drive (no RAID) to 2 drive (RAID 0), and then not as much a boost (but still a boost) going to 4 drive (RAID 0).

I'm only going by my manual, have only got the 1 HDD so i can't experiment!

JayMan