View Full Version : Booting off RAID 0 in New G4?

02-25-2001, 08:47 PM
I know that Apple has not supported booting off of a RAID 0 volume and you have to do tricks to make it do so from reading your comments here. Does anyone know if this has changed with the new G4s? Does anyone with a new G4 boot off one?

02-26-2001, 08:36 AM
still no go. Been happy booting of the internal ATA drive with dual Cheetahs as my work volumes. Will eventually get the ATA drive out of there and install another Cheetah.


02-26-2001, 11:35 AM
I wonder if OS X will fix this. If you don't have a system folder on the ATA drive, will it boot off the RAID?

02-26-2001, 12:41 PM
I first tried it when I got the dual 533. Its my only workhorse here now so I don't dare try it again. OS X looks like Apple will have to get it done. Don't know why they removed the option.


03-04-2001, 11:00 AM
This is sort of related to the original posting.. Some of the earlier PowerMac G4 Server boxes - I think the ones shipped with either ASIP or OSX Server - shipped with SCSI boot drives.

If that's the case, then would it not be possible to build a bootable SCSI Raid0 array using such an architecture?. i.e. dig around and find someone selling a SCSI-based Server G4 box on closeout (as is our school bookstore)

Or am I missing something subtle?. The new ServerG4 machines apparently will only ship with IDE drives.


03-05-2001, 01:17 AM
MacOS wants to boot off a fixed volume, whether IDE or SCSI. Booting off striped or mirrored arrays in New World Macs is not endorsed by Apple, and not supported. It is possible to hack around this, but we're a little unnerved by Apple's implacable silence in this regard, and prefer to wait until Mark James at SoftRAID tells us they have reverse engineered the boot sequence and can support and endorse it.

03-05-2001, 02:20 AM
Ahhh - I see - So we could in fact boot off a SCSI drive but as long as it's a non-RAID volume



03-05-2001, 02:24 AM
I've contacted an Apple Systems Engineer on this issue and will let you know what he says.

Has anyone tried to do the RAID issue under OS X?

Here's a TIL article that explains Apple's stance on this (at least as of its publishing):

03-06-2001, 01:39 PM
interesting. I remember this TIL....I read it a long, long time ago.

it states that you can actually boot off a RAID 1 mirror, which I thought was not supported.

it will be interesting to hear what your pal says....we're long overdue for an authoritative update on this.


03-08-2001, 05:21 PM
I finally got a response from the SE and he's looking into it. I'll keep you posted.

03-09-2001, 01:00 PM
we have worked with an Arena RAID 5 under OSX. When we can get it to work at all, it is visible to the OS.

testing continues...

03-09-2001, 01:56 PM
WOW!! That's great!

I'm not familiar with that one, it's hardware, right?

I'd love a software RAID 5

03-09-2001, 02:23 PM
Softraid is working on a raid 5 solution. My hopes are it is finished and they will release it with the OS X update.


03-09-2001, 02:29 PM
That would be AWESOME. I asked mark about it about 6 mo. ago, he didn't have any new news then. How many drives do you think would be optimal if they were do get it done? I know that sometimes the processing overhead for x number of drives bog it down.

03-09-2001, 02:46 PM
Actually, speaking of booting off a RAID 1 mirror, I'm doing this right now on my G3 (also New World arch.). Perhaps I'm doing a little bad mojo, perhaps not, but I too read the Apple TIL about this and figured I'd give it a shot. http://macgurus.com/infopop/emoticons/icon_smile.gif

G3/400, OS9.1
Miles2 (latest firmware) with bundled cables.
two (2) 9GB Quantum Atlas 10k drives, installed internally
SoftRAID 2.2.2

Each drive has two partitions, one ~700MB, one ~8GB. I mirrored the two 700MB partitions and boot off that volume, and striped the two 8GB partitions in RAID0 and use that volume for all my apps, games, etc. Everything seems to be working just fine. The only pain in the butt is rebuilding the mirror every time the G3 goes down hard (which, when using MS Office98, is quite often), but even then it's only 700MB so it's about 1-2 minutes. I'm getting about 25-30 MB/s on the boot volume and bursts of 50 MB/s on the striped volume, so I feel like I'm getting the best of both worlds.

I would assume that G4 machines would be able to do this as well?

Anyway, just my two cents...

David French

03-10-2001, 12:58 AM
according to that Apple TIL, it is likely.

12-07-2002, 03:26 AM
I know this is a really old thread. But I have a dual 1 GHz mirrored drive door G4 and I just (2 hours ago) setup two internal IDE drives to boot from a RAID 0 volume. Both disks are one big volume. Apples disk utility won't allow you to partition the drives and then assign different partitions to different RAID disks. It's an all or nothing deal.

I'm going to test Mirroring the drives next and see how that works out.

Gregory Davis

12-07-2002, 11:53 AM
My understanding is that there is a ~$130 SIIG card you can get that will allow you to do hardware RAID 0 on your machine (I know someone with a DP1.25 that did it). This may be what you need to get the perfomance you wish.

Specs: http://www.siig.com/products/ide/specs/UltraATA133_100RAID_S.html
Store: http://www.cruxworks.com/cruxworks/showdetails.phtml?pc=AMY81&cw=160081