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Cannot delete/erase mac mini raid partition

Posted on 2012-03-14
Medium Priority
Last Modified: 2016-12-08
Hi There

I have a Mac mini that had OSX Leopard Server on it. We installed Lion Server on it when it first came out and put it in to a small school and gave them all the details. They were having issues and asked us to sort it all out. We had no passwords so decided to re-install the OS.

This was not a very good idea. On an internet restore it keeps stalling and telling me that I need to go to the disk utility and delete the main partition. When I do this it has the two 500GB drives combined to a master stripped drive. However everything is locked and will not allow me to make any adjustments.

Is there any way to unlock these drives and allow me to reset all the partitions and Raid configuration?

Question by:doey
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LVL 10

Expert Comment

ID: 37723644
it lools like something went terribly wrong. I would recommend to boot from DVD and repartition drives and recreate mirror.

Author Comment

ID: 37723759
The mac mini server edition does not have an optical drive. However the OS is on a USB stick and I can boot from that. From this I can get into the disk utility which I believe is the only place to perform the actions required. I have listed the proble that I get from the disk utility above.
LVL 47

Accepted Solution

David earned 2000 total points
ID: 37725881
UNIX 101.  Learn how to use dd and the terminal interface.

If you want to blow the partitioning away, then you use dd to write zeros to the appropriate device, as in:

sudo dd if=/dev/zero of=/dev/xxxxx  bs=1024k count=1  

Above will put zeros in the first 1MB of /dev/xxxxx
To figure out what device(s) you want to blow away
enter mount
and it will give some cross-reference info..  (Below shows my system which has a time machine on network, an iSCSI target, parallels running windows and a few other things ..)

To blow away everything in /dev/disk0   use /dev/disk0 as the "if="  to blow away contents of my bootcamp  partition in disk0, you would use /dev/disk0s3 in my case.

(Warning, there is no Are-you-sure.  If you blow away something, it is gone, even if you tell it to blow away the system disk you are booted to.  It will gladly do so).

Choose the device wisely and make sure you are careful about what you want to blow away.

davidslaptop:~ david$ mount
/dev/disk0s2 on / (hfs, local, journaled)
devfs on /dev (devfs, local, nobrowse)
/dev/disk0s3 on /Volumes/BOOTCAMP (msdos, asynchronous, local, noowners)
map -hosts on /net (autofs, nosuid, automounted, nobrowse)
map auto_home on /home (autofs, automounted, nobrowse)
map -static on /Volumes/mounts (autofs, automounted, nobrowse)
afp_3YlCHx3dINti2MIyao0l5AQ8-3.2e00000e on /Volumes/TM_David (afpfs, nobrowse)
/dev/disk1s2 on /Volumes/ANSITargetOnJeeves (hfs, local, journaled)
vfstool@prlufs0 on /private/tmp/5313/C (prlufs, nodev, noexec, nosuid, synchronous, mounted by david)
vfstool@prlufs1 on /private/tmp/5313/E (prlufs, nodev, noexec, nosuid, synchronous, mounted by david)
vfstool@prlufs2 on /private/tmp/5313/I (prlufs, nodev, noexec, nosuid, synchronous, mounted by david)
davidslaptop:~ david$

Open in new window

df -H shows supporting information

davidslaptop:~ david$ df -H
Filesystem                                Size   Used  Avail Capacity  Mounted on
/dev/disk0s2                              466G   388G    77G    84%    /
devfs                                     205k   205k     0B   100%    /dev
/dev/disk0s3                               34G    48M    34G     1%    /Volumes/BOOTCAMP
map -hosts                                  0B     0B     0B   100%    /net
map auto_home                               0B     0B     0B   100%    /home
map -static                                 0B     0B     0B   100%    /Volumes/mounts
afp_3YlCHx3dINti2MIyao0l5AQ8-3.2e00000e   839G   296G   543G    36%    /Volumes/TM_David
/dev/disk1s2                              107G    52G    55G    49%    /Volumes/ANSITargetOnJeeves
vfstool@prlufs0                            34G    29G   5.3G    85%    /private/tmp/5313/C
vfstool@prlufs1                           100G    40G    60G    40%    /private/tmp/5313/E
vfstool@prlufs2                           106G    52G    54G    50%    /private/tmp/5313/I
davidslaptop:~ david$

Open in new window

So i above ,  /dev/disk0s2 is a partition on the /dev/disk0 and it is 466GB total, and /dev/disk0s3 is partition on the same disk used by BOOTCAMP at 34 GB,   The rest is other stuff.  You would have a /dev/disk1 presumably which has some number of partitions on it.

To blow away 100% of a physical disk
dd if=/dev/zero of=/dev/disk03 bs=1024k
(Will blow away all of physical disk /dev/disk03)

Author Comment

ID: 37726475
WOW. Thanks dlethe.

This is the type of answer that I was hoping for. I have yet to try it out. But when you say "blow away" I presume you mean erase everything. If that's the case then this is exactly what I want to do. I want to start totally afresh.
LVL 47

Expert Comment

ID: 38044102
Yes, I mean write zeros to the disk, technically that doesn't mean erase everything, it means to overwrite the 1s with zeros.

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