Raid on the same IDE channel?

[Suthern]

I've just bought a new motherboard which supports RAID. It only has two IDE headers though. I need to connect the two 80gig Maxtor HDs, and a DVDrom drive to this MB.

I couldn't find any benchmakrs for it, but what would the performence drop be if I use a RAID 1 on Master and Slave on the same IDE header?

I know it would be slower then if I stuck both maxtors on thier own cables, but then there wouldn't be a header left over for the CD/DVD drive.

Does anyone have links to benchmakrs comparing same-ide-cable and multiple-IDE-cable RAID 1 performance? Thank you very much!

-Suthern

 

[Suthern]

I meant RAID 0 - Stripped... not mirrored

-Suthern

 

[Chacalinc]

if you are using the SAME ide bus for both disk drives, performance will be affected... try to use the 2 buses, 1 per drive, no matter where the CD is.

cheers.

 

[Wyse2Know]

With the arrival of Ultra-ATA (aka UDMA aka PIO-5), the IDE bus no longer defaults back to the slowest IDE device. In other words, there is no objection in Configuring your CD/DVD drive as Primary Slave, your HDD will continu to work @ his best setting (probably UDMA133). However, the IDE bus is still able to speak to a Maximum of ONE device at a time, subsequently, putting both HDD's on the same IDE bus will slow down your configuration considerably. (altough normally the IDE bus will have a lot more bandwidth than used by your HDD's).

So I agree with Chacalinc, you should configure your PC as follows:
Primary Master: HDD-1
Primary Slave : CD/DVD
Secundary Master: HDD-2
Secundary Slave : None/Other

 

[hcyen]

Just curious, why do you want to use Stripping not Mirroring?

What is the actual speed difference?

 

[Suthern]

Well, here's a page I found that benchmarked various chipsets in various raid configs.

http://www.gamepc.com/labs/print_content.asp?id=serialcompare&cookie_test=1

look at the tables for Raid 0
Read speed average ~87 to 52 MBps. (max 138MBps)
Write speed average 46MBps to 38MBps

then look at the table for Raid 1
Read speed av ~65 to 45 MBps (max 74.7MBps)
Write speed av ~35 to 21 MBps


Raid 0 looks faster for both reading and writing. Although we did not get to see a max writing speed in the tables, the average tells us something.

My system is going great, and is using RAID-0, with two 80GB drivers. One HD has its own IDE channel, and the 2nd HD shares the channel with a DVD-RW.

-Suthern