Yesterday we talked about the ideal backup solution. Today we are going to look at how to implement this solution on OS X. The disk utility with OS X allows you to create a live copy of your hard drive that can be started up and run just like it is your computer. You can even create the backup while using your computer.
As far as I know, this process will only work when you are using a firewire hard drive. I haven’t had any luck booting OS X to a USB drive, so while you may be able to make a backup with a USB connection, I don’t think you can make the backup bootable.
The Disk Utility application stored in your Application > Utilities folder. It is simple to use, but you have to pay attention to make sure you are copying your data in the correct direction–you don’t want to accidentally copy an old backup over your working data.
1. Launch Disk Utility
When you launch Disk Utility, it will show you a list of the available drives on your computer. In the example, I have my internal hard drive (a 74.5 GB hitachi) with a single partition called Macintosh HD. My 232 GB LaCie drive contains three partitions. The Backup partition is where I want to put my data, so I select it.
2. Select Restore
In the right hand side of the application, I’m going to select the Restore tab. I’m going to “restore” my internal drive into the Backup partition on my external drive. This will make the Backup partition into an exact copy of my local drive–even changing its name to Macintosh HD. While it is called “restore” it is really just creating a copy of the drive.
3. Determine Which Drive Will Be Copied
With the Restore tab selected I simply drag Machintosh HD into the source and Backup into the destination and tell it to erase the destination. WARNING: Always double check carefully to make sure my source and destination are correct and that I’m not accidentally going to overwrite important data.
Let me repeat that. Always double check to make sure your source and destination are correct. You want to copy from your local drive to your external drive. Once you’ve done one backup, the partition on the external drive has the same name as your internal drive, so you have to make sure you are putting things in the correct spot–even if the names are the same. Take a close look at your local hard drive icon to make sure you have the right one in the right place.
4. Start the Restore
Clicking on the Restore button starts the process. It isn’t particularly fast. Ideally you should make the partition to which you are restoring as close in size to the original in order for the transfer to be as efficient as possible. (If you want to find ways to speed up the backup, do a search for information about “block level” copying in OS X to external drives.)
While it is possible to use your computer while doing this backup, I would recommend closing out of all your programs and letting the computer do the backup without running anything else. It reduces the chance that something might go wrong or that something might be backed up in a state that relies on internal memory to be valid. I have never had this happen, but it is a good precaution.
Booting the Drive on Another Computer
If you ever need to bootup the drive on another computer simply tell that computer to start using the external drive as the startup drive. This is done from the System Preferences using the Startup Disk icon.
Once you reboot the system, it should boot up using the external hard drive as if it is the system you backed up originally.
Moving the Drive Contents Back to Your Original Computer
Once you get your computer repaired, you will probably want to move the contents of your external drive back to your computer. You can continue to use it from the external hard drive until you have some time to let it run for a few hours. To move the data back, follow the instructions again, but this time restore the disk from the external drive to the internal drive.
To restore from your hard drive, you’ll simply perform the restore process, but this time moving the data from your external drive back to your computer’s internal drive.
Automation and Rotation
The best backup is one that happens automatically. It is possible to schedule this type of backup from the command line. I would suggest using two partitions and alternating between which one you backup to. That way you’ll have a fall back if something goes wrong.
I generally do the backup manually about once every few weeks, but I have other ways of backing up files that change frequently. Whenever we are getting ready to travel, I will do a backup so I have the current state of my computer in case it gets lost or stolen.
Other Operating Systems
You can probably do similar backups with other operating systems. Most of the time you’ll need to buy some type of disk imaging software like Ghost. If you know of an easy way to create hot backup in Windows or Linux, please let me know in the comments.