RAID 1, booting and SuperDuper
 

I've searched the forums for others with RAID problems and haven't come across this one.

I have a new 4 disk MacPro. Drives 1 and 2 are arranged as RAID 1 (mirrored) from which the machine boots. Disk 3 is some scratch space and 4 is my test backup (and will be replaced by an external firewire for offsite storage).

I wanted to check my backups will work properly. I installed the OS on the RAID, backed it up to disk4 (using SD) and can boot from either the RAID or disk 4. Great, all looks good. I then wiped the RAID (actually re-created it from the start) and used SD to copy everything from disk4 back onto the new RAID. The machine now fails to boot from the RAID, I get the spinning wheel on a grey screen with a NO GO sign on it. Nothing works.

NOTE - when in this state I couldn't get any of the 'normal' command boot key sequences to work, nor could I open the CD to load from that. The only way I could get out of the mess I'd created was to connect the machine to another Mac in target mode (use firewire and hold down t during boot on the afflicted machine). I could then open the CD, run disk util, change the boot drive and get back to square one ....

Is this a known problem? I've actually reproduced it with a fresh install from CD. I'd assumed SD should accept RAID or single disks interchangeably, but it looks like I'm wrong.

Many thanks
David

As I recall, there were some RAID bugs in OSX's handling of the kernel extension cache that were fixed in 10.4.9. Are you doing this with 10.4.9?

I know we do work properly with RAID sets (in fact, we're even suggested by SoftRAID due to their own internal testing)...

This is a vanilla install from CD onto the Mac Pro, then fully patched using Software Upgrade. The machine reports it's using 10.4.9. I found this which reports 10.4.8 problems with RAID corruption:
http://docs.info.apple.com/article.html?artnum=304511
Also found this Macworld feature which reports the same thing:
http://www.macworld.com/2006/11/feat...mp1/index1.php
dated last November (he reports identical symptoms to those I see).

I may try again tomorrow ... but it sounds from your answer that there's nothing fundamentally problematic combining RAID disks and usable backups with SuperDuper.

Thanks
David

That's right: there's nothing fundamentally wrong.

Something to try: use kextcache to recreate the cache on the RAID set, while booted from another volume. You'd use something like (in Terminal, of course):

sudo kextcache -f -u "/Volumes/the-RAID-set"

You could also use SD to restore your backup to a single drive, and then setup your raid using this trick to create a raid without reformatting:

http://www.afp548.com/article.php?st...40827122302975