Multiple HD:Raid or IDE & Question about IDE RAID

[SuperNoOne]

Ok, I'm building a new system, and want to use and older 40x CD-Rom and an old 3 Gb HD, plus a New HD, probably a 30 Gb IBM 75GXP. My two doubts are:

1. 
   I read somewhere that altough in theory when you connected a slower slave to a faster Master, both would be working on the faster drive mode, in practice what happens is that both drives end up working restricted to the slower drive. So in my case The ATA-100 IBM would be forced to work in ATA-33 like my slave HDD. Now is this true? Could it just be that no IDE HDD can read more than 30 or 40Gb except in bursts, and so in the end it might seem like the slave is slowing down the master, or is it that you HAVE to put both drives working in ATA-33 (for example).
   
   About RAID, what would happen if i put my ATA-100 IBM and my 3Gb HDD (probably ATA-33)in a Raid array? First would it work? Second Would there be a speed increase or decrease, i mean, could the slower one slow down the faster HDD or not?
   
   Third, One problem of striping is that you double the chances of data loss. It was first done for scsi, and i'd guess that one reason they didn't come up with it before was that SCSI drives are much more reliable than IDE drives, i mean it's less likely that a SCSI drive will intercourse up than and IDE drive. So, what i'm trying to say is that RAID was great for SCSI drives, but maybe not so great with IDE drives. So, do you think that IDE RAID is kind of a fad, and that in a couple of month's time people will end up leaving it behind because it's not so cool as it seems?

 

[BoberFett]

I'll bump this, hoping someone can give you some more conclusive answers than I.

Unless things have changed with these new IDE RAID cards, the drives in a RAID configuration need to be the same size, so I don't think it's even an option. Maybe you could create a partition of 3GB on the main drive and stripe it with the second drive, but since your new drive is so fast, striping it with an old junky hard drive might actually make it slower.

In your situation, if you really want to keep the old hard drive, put it as the master on the second controller, the CD-ROM the slave on the second controller, and the main drive obviously as the master on the first controller. That should give you pretty optimal transfer rates in various situations.

Personally, I'd never run RAID 0 as there's no fault tolerance, and in my experience the speed increase is negligible.

 

[Ulysses]

I have the Promise FastTrak100 RAID controller card and a couple of IBM 75GXP's that I may set up in a RAID 0 this weekend if I have time. The manual is very good. It recommends that both drives be the same for max performance, although 2 drives that are different should still work. But the size of the RAID will be limited to twice the size of the smallest drive. If you put an ATA/33 HDD on a cable with an ATA/66 or ATA/100, then both drives are limited to the slowest mode. The newer IBM HDD's will run, though, at a bit better than ATA/33 speed in normal operation.

A RAID is mostly beneficial in "professional" apps rather than "everyday" things, although they can be tuned for different type uses. As far as I know, the risks of striping are the same for IDE HDD's as for SCSI HDD's - if one of the drives fails the RAID and its data are destroyed. So you need to backup regularly, since you really have no Redundancy.

Maybe take a look at Promise's site and download the manual for more info.

P.S.
If you really think that you will benefit from a RAID, you should probably pick another 30 GB 75GXP.