Raid 0 on PPC Mac Mini

[RobinS]

I use an adaptor to run a full size 7200 rpm IDE hard drive in my 1.25 ghz Mini. It converts the notebook plug to a regular size IDE plug. I have a spare channel on the IDE cable of course which I usually use for a full size DVD burner.

I heard that there was a comparison using an Xserve between Raid 0 using a hardware controller and the software version built into OS X. Apparently the software version was only about 5-10% slower. This got me thinking.....

Why not use 2 IDE drives on my IDE cable in Raid 0? I have another 250 gb drive here that I use for backup (that could work with my existing 250 gb), so as soon as I pick up a 3rd for my backup I'll be set. I was cloning my hard drive so I needed the same size as my working drive which is almost full all the time, but now I realize that it would be better to reinstall the OS if I have a hard drive problem (they do seem to accumulate over time just like Windows) so I won't need as large a hard drive for backup as before.

Can you see any problems with this idea?
Would it run noticeably faster?
Its particularly attractive because I was going to get a larger hard drive anyway. Now I just have to buy the backup and I'll have twice the space. And an external USB2 or Firewire case for the DVD burner of course. Do you think it makes any difference between USB2 and Firewire? Will USB2 be slower in any way if I'm just reading and writing DVD's?

[Decade]

Yes, I see a problem.

If I remember correctly, the drivers and drives for parallel ATA don't allow the drives to be both doing stuff at the same time, which pretty much negates the speed advantage of RAID-0. Maybe if the drives' on-disk cache is large enough for your work and have write-back caching (an unsafe technique), then it might work for you, but I doubt that that's the case.

Serial ATA gets around that problem by not allowing more than 1 drive per channel. SCSI gets around that problem by allowing drives to disconnect/reconnect on the bus. I'm not sure about Firewire. I'm reasonably sure that USB doesn't allow disconnected operation.

Firewire is supposed to take less CPU time than USB, leaving more time for tasks like managing the cache and readahead buffer.

[Captain Code]

I don't think you can boot off of an OS X software RAID. I haven't even found one that can boot via hardware RAID cards. The only thing I think would work is the external Firewire RAID 0 enclosures.