Raid 50

O

osxp4me

Registered
I have an XServe RAID hooked up (via PCI fibre-channel) to a XServe G5.

The RAID is configured level 50 which requires both hardware and software configuration (hardware will RAID level 5 each controller and software RAID to stripe the level 5's together [RAID 0]).

Of course, as is typical with Mac (argh), I tried upgrading the XServe G5 to 10.4 and I got some stupid error during the "Preparing Disk" phase. Thank god this didn't render the system useless. Anyways, I still need to completely erase the volume and install 10.4 fresh.

My question is, can you erase a volume which has RAID 0'ed something since it is a software RAID? Hopefully, I don't know what I'm talking about (which is true when it comes to RAID representations within an OS) and it is perfectly safe to do so.

Thanks. I'm new to the site by the way.
 
Now I might be way off base here but I don't think that you can have the system volume on a software raid array. Hardware is not a problem, but in the case of software how can the system boot from an array that it doesn't understand until it is booted.

Now there may be a fancy way to boot from part of the disk and then remount the root once enough of the kernel is up and running but that seems a bit involved. IIRC the system disk could only be a normal volume, no software raid no lvm goodies or anything. Now that may well be incorrect or dated so caveat emptor, I am just a hair away from totally talking out of my nether regions. But if you don't care you can always blow the software raid partition away with no problem.

Hope that helps and maybe a more informed commenter will come by too correct me on this one.
 
Perhaps I didn't explain things clearly enough. Perhaps I didn't follow your response (Lurk). It's a much simpler problem that you're assuming (I think). Let me go through this again:

I have a XServe G5 with a single boot volume containing OSX. This is completely and utterly separate from the XServe RAID. At the time the XServe G5 was configured, the RAID never even existed.

Upon receiving the XServe RAID, I hooked it up to the XServe G5 using PCI Fibre-Channel and used the XServe RAID Admin Utility to allow remote access to the RAID itself. Standard procedure here. Now, with the RAID Admin Utility, I applied a RAID level 5 to each of the controllers (there are 2 separate controllers on the XServe RAIDs). My understanding is that when using the XServe RAID Admin Utility, you are applying a "hardware RAID". Logic that cannot be lost.

Now, once this level 5 configurations are complete, OSX sees the RAID as 2 distinct volumes. To span these two volumes together (so that they look like a single volume) you must stripe them together (RAID level 0) using Apple's Disk Utility. To my understanding, this is a "software RAID". I have no idea if this logic can be lost upon erasing the Operating System which performed the software RAID (and hosts the unit).

Now, if I were to erase the XServe G5's boot disk to reinstall OSX, would the new OS installation have any idea that the RAID is a level 50? Another way of saying it would be: if the OS which had performed the software RAID is erased, would any knowledge that the RAID controllers being spanned into a single volume also be lost?

Thanks
 
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