Using a Seagate Expansion Portable Drive to back up your Mac
John Gruber’s recent hard disk failure, combined with some travel plans that I have, made me realise that I need to improve my backup strategy. I currently have a 500Gb Iomega FireWire external hard drive permanently connected to my iMac, so that Time Machine can do its backups. But as Gruber points out, you can’t just boot from your Time Machine drive in the case of catastrophic disk failure: you need a bootable backup disk. I was also worried that if something happened to my iMac while I was away, such as theft or destruction by fire, the Iomega might be lost as well.
So I decided to buy a new external drive and back it up with SuperDuper, which I have used before. The great thing about SuperDuper is that it comes in a free version that you can use to create complete, bootable backups of your main drive (the paid version lets you do incremental backups, whereas the free version erases the backup drive each time, so it takes much longer to do regular backups).
I looked on Amazon for a nice external drive. All of my external drives to date have been the large, powered ones, because they are generally cheaper, and also faster; but finding yet another socket on the power strip for one more wasn’t something I relished. Since I only intended to use it for periodic backups, relying on Time Machine for my day-to-day backups, and since prices seem to have declined, I decided on a Seagate 500Gb portable drive, the Seagate 500gb Expansion External Portable Usb 2.0 Hard Drive
It arrived from Amazon this morning, and I was somewhat alarmed to see all the Windows compatibility stickers all over it, with no mention of Macs. On opening the box I found a really small and light drive, not much bigger than an iPhone. Plugged into the iMac, it was attached in the Finder, and showed a few files, including an Autorun file, and a Seagate folder containing some junk.
First problem came when trying to delete these files; the Finder couldn’t do it. I fired up Disk Utility and saw that it was formatted as an NTFS drive, not a total surprise as that is the latest Windows file system! So I just reformatted the drive as Mac OS Extended (Journaled), and proceeded to do the backup on SuperDuper.
The tradeoff with the external power supply soon became apparent; the drive is not very fast, and backing up 136Gb took a couple of hours. The next annoying thing happened when I tried to set the drive as the boot volume, to test the backup by actually booting from it. The drive did not appear in the selection window.
A quick scan of the SuperDuper help site revealed a possible problem: OS X under Intel can boot from USB drives (unlike PowerPC Macs) but not if the disk is partitioned using Master Boot Record (MBR). A quick check with Disk Utility showed that the disk was indeed so partitioned (and why wouldn’t it be?). Aaargh!
So if you’re going to use this little drive as a SuperDuper bootable backup, remember to repartition the drive itself, and don’t just reformat the volume.
Finally, some wise words from Gruber:
Hard drives are fragile. Read as much as you can bear to about how they work, how incredibly precisely they must operate in order to cram so many bits onto such small disks. It’s a miracle to me that they work at all. Every hard drive in the world will eventually fail. Assume that yours are all on the cusp of failure at all times. It’s good to be spooked about how long your hard drives will last.
Make sure you are prepared for when yours goes phut. Not if. When.
April 6th, 2010 at 4:11 pm
I just bought one of these (also prompted by Gruber’s experience and Merlin Mann’s follow-up). I used Disk utility to zero the drive, and partition it as Mac OS Extended (Journaled). I then backed up my 120GB (also took me about 2 hours), and was similarly disappointed that the new volume does not show up as bootable.
What should I do differently at partitioning time to NOT use MBR?
thanks!
Paul
April 7th, 2010 at 1:02 am
Hey Paul, great minds think alike!
The thing to remember about hard drives is that there is a difference between the physical device itself, and any partitions that you create on it. Before you can create any partitions you need to set up the blank disk to accept these partitions, and this process (sometimes called a low-level format) kind of sets out the basic disk organisation, kind of like painting lines on a field. There are a number of ways of doing this, and the method favoured in the PC world is the MBR or Master Boot Record, which is named after the way the very first blocks on the disk are formatted. These blocks tell the computer how to bring the disk up, and how to boot it if you are trying to do that.
In the Mac world, the basic way to set up a disk is to use the GUID partition table; this has a different bit of code to tell the computer how to boot it. Macs can read disks that are set up with MBR, but can’t boot them. So you need to go one stage deeper when you format your new disk to make it bootable; just zeroing it with Disk Utility and creating a new Mac OS Extended partition is not enough.
To do this, in Disk Utility, notice that your partition is set slightly indented in the left-hand pane, directly under the drive’s hardware component, which is listed separately, and is set flush against the left margin of the left pane. To do any low-level work, you need to select the hardware component by clicking on it (not the partition, which is probably what you selected last time).
Now when you click on the Partition tab in the right-hand pane, you will see the volume scheme. You can now choose a new volume scheme. Pick one that has the GUID Partition Table as the partition map scheme, and then add a single partition using Mac OS Extended (Journaled) as the volume scheme. (You need to do this as re-creating the partition map scheme will erase the drive). Once this has been done, you will then be able to re-run Super Duper, and this time, the backup should be bootable!
April 7th, 2010 at 3:49 pm
Thank for the help. I re-partitioned using the GUID scheme, re-ran SuperDuper to create a complete backup, and booted from the Seagate about two hours later. Now that it works, I gotta get back to Fry’s electronics before they sell out! These drives are currently $39.99 (one per customer).
Thanks again!
May 14th, 2010 at 1:03 pm
Hi
I’ve just bought a Seagate Expansion external hard drive 1TB and i wanted to attach it to my Airport Extreme device so that the entire family can back up their systems as well as using it as a central location for family photo’s, music and films.
Every time i plug the hard drive into my laptop Time Machine comes up and asks me if i want to reformat the drive so as to back up everything on my Mac.
I don’t know what to do and it appears that you guys know exactly what you’re talking about so any help would be greatly appreciated!
We’re a family with 5 laptops, 2 Mac’s and 3 Windows run laptops. Please advise on the best solution for me!
Thank you!
May 16th, 2010 at 5:41 pm
Hi Kash,
You need to let Time Machine reformat the drive, because the drive came from the factory ready to use with Windows. To use it on a Mac, it just needs to be reformatted, I think you could just follow the prompts. You won’t need to worry about any of the stuff I spoke about with Paul.
I haven’t tried attaching a drive to an Airport Extreme so not too sure how well that works. I think it will only back up the Macs automatically, you may need to manually back files up onto it from your Windows machines.