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How to clone a disk
with Disk Utility for the Mac
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FAQ is the
acronym for Frequently Answered Questions.
Note: Users with T-1 or newer chips must have
their security turned off for the cloning procedures
to work.
Introduction:
Cloning is the procedure by which you
create a backup that is identical to a bootable
system on an external drive. It also has been
called mirroring a hard drive. With some software
like Retrospect by EMC, you
create a clone using a duplicate command and
selecting the source and destination volume, once
you make sure the permissions are set right. With
Disk Utility the procedure of the permissions is
similar, and will be outlined below. Note, with
Mac OS X, backups which are bootable only include
Firewire drives, and drives on an IDE bus
recognizable by the system as a bootable drive.
The purpose of making the drive bootable is that
you can test the most basic function of the
operating system in the clone to see if it will
work as well as the original. If it does, chances
are the clone is easily recoverable. The procedure
outlined below can be done with Disk Utility in
Mac OS X 10.4.2. It has not been tested with any
other version. A reader of this article suggested
it might be better to do this procedure by booting
off the installer disk, which has Disk Utility in
the Utilities menu of Tiger, and previous
operating systems in the File menu. Booting from
the installer disk is usually done with the
startup manager: If you find something in the
following procedure which could be edited, please
sign the guestbook:
A. Setting up the clone.
1. Create an admin user in Apple menu
-> System Preferences -> Accounts with no
Startup Items, and log into it.
2. Ensure that the destination drive you want to
backup to is available on the desktop. Note, this
drive can not have any data content you want to
preserve, since this procedure overwrites the
entire drive.
3. Open Disk Utility from your boot drive ->
Applications folder -> Utilities folder.
4. Select the destination drive within Disk
Utility, and click on Erase. From the Erase
section, erase the hard disk.
5. Once that drive is erased, click on the dock or
use command-tab (command is the Apple logo key) to
make the Finder application active.
6. Select the erased drive, by clicking on it
once, and ensure that the Ownership and
Permissions are not ignored in the window which
appears when you go to the File menu and select
Get Info. Uncheck its checkbox if it is checked.
7. Switch back to Disk Utility and select the
Restore section of Disk Utility.
8. Drag the destination drive from the Disk
Utility left sidebar into the white field marked
Destination.
9. Drag the Source drive from the left sidebar and
put it in the white line marked Source.
B. Performing the clone
1. Click on Restore. This procedure may
take several hours. A 100 GB clone took 7 hours on
Firewire 400 on an iMac G5 with 2 GB of RAM.
C. Testing the clone.
1. Go to Apple menu -> System
Preferences -> Startup Disk. The clone should
now appear in the startup disk list.
2. Select the clone from the Startup Disk listing,
and click on restart.
3. If the clone appears in the upper right hand
corner as an icon above the source, the clone was
successful.
For additional backup options, check my Backup FAQ. I was able to
use Silverkeeper mentioned on that FAQ to update my
clone made with Disk Utility, with a more current
clone simply by following its own cloning
procedures. |
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