Adding software RAID to installed system

[Dan Shoop]

At 10:59 AM -0800 2/6/07, Andrew Oliver wrote:
>On Feb 6, 2007, at 7:39 AM, Fabian Peters wrote:
>
>>Hi folks,
>>
>>Has anybody successfully created a RAID1 without erasing the 
>>existing boot disk (possibly even w/o rebooting?) on OS X Server 
>>10.4? Apple's "Getting Started" guide states it's ok:
>>
>>"If the target disk has a single partition and the second physical 
>>drive has a single partition and no data, you can set up RAID 
>>mirroring after installation."
>>
>>Which I figure is what I'd like to do but I feel the wording is a 
>>bit vague. Of course in any case the usual caveats to back up 
>>beforehand do apply...
>>
>>Thanks for your insights
>
>It is possible to do. You may need to reboot, and you can't do it 
>through the GUI.
>
>Assuming your two drives are disk0 and disk1 (use diskutil to 
>verify), and disk0 is your current boot drive
>
>1) diskutil enableRAID mirror disk0
>This will create a degraded mirror RAID, disk2, consisting of the 
>boot drive (disk0) and nothing else.
>
>2) diskutil repairMirror disk2 disk1
>This adds disk1 to the existing RAID disk2
>
>3) Wait (use diskutil checkRAID to check progress)
>
>I've done this many times, and it's worked most of the time. 
>Sometimes, though, the repairMirror fails. That's usually been fixed 
>by booting from DVD and running repairMirror again - in other words 
>there's a higher success rate when you do this on a non-live drive, 
>but I haven't worked out the exact conditions that cause it to fail.

I've experimented with this quite extensively, and it works rather 
well but I still wouldn't trust it. I'd want a full, bare metal 
backup if I was doing it to my system disk.
-- 

-dhan

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Dan Shoop                                                   AIM: iWiring
Systems & Networks Architect                      http://www.ustsvs.com/
shoop at iwiring.net                                http://www.iwiring.net/
1-714-363-1174

"The wise man doesn't give the right answers, he poses the right
questions." -- Claude Levi-Strauss

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