I might as well have asked my poodle to make coffee
Al Fasoldt's reviews and commentaries, continuously available online since 1983


How Time Machine saved my bacon when my main drive and its disk clone both died

April 23, 2010

By Al Fasoldt
Copyright © 2010, Al Fasoldt
Blog item posted April 23, 2010

   I teach workshops that emphasize cloning your computer's main hard drive (creating an exact, byte-by-byte, bootable backup disk) in case the inevitable happens when you least expect it. (I know, I know; that's Murphy's Law.) And I've been cloning my Macs' internal drives for years, doing it every day if there is a lot of activity or every few days if there isn't.
   Because I'm a personal friend of that guy Murphy, I also run Time Machine on my Macs. It makes incremental backups every hour and has the simplest interface of any backup method the world has ever known. (Actually, I'm being reticent. Time Machine has the most incredible interface of any backup system, period.)
   So right when any interruption in my work would surely come at the worst possible time, my main hard drive in my MacBook Pro corrupted itself totally. Wouldn't even boot. So I told the Mac to boot from my clone drive.
   Ha! I might as well have asked my poodle to make coffee. The clone was totally corrupted, too. Was it because it was a clone of a corrupted main drive? Not on your life. The main drive was fine when I made that backup clone. But for whatever reason, the clone was unusable. Totally kaput.
   That left me with nothing more than my Time Machine backup. I'd never used TM to do a full restore before. (I love the way I get get back something I accidentally deleted. But restore an entire system from an incremental backup? You gotta be kidding.)
   But that's what I was left with. I tried restoring twice with bad results (missing files). The third time, I paid attention to the questions on the screen (don't say anything or you're out of the class) and got a usable result. There were a few things missing (for no explicable reason) but I was easily able to reinstall them.
   The moral of this story? Let Murphy have his due. Test your cloned drives right after you make them, so you can remake a bad one.
   If you're a Mac user, you should look into the two major cloning programs. One is Carbon Copy Cloner; the other is SuperDuper (which has a "!" at the end if you spell it the way the SuperDuper folks do. I usually avoid confusing spellings.). Both let you boot up right from your cloned drive. (That's one of the ways Macs make computing much simpler. A Mac can boot from any external drive that's been set up as a boot disk -- no need to stick the disk into your computer to boot from it.)
   CCC can be used for free, although the author appreciates payment. Get it from www.bombich.com. SuperDuper can be tried for free and costs only $28 if you like it. It's from www.shirt-pocket.com.
   Added note:
   A reader asked why I was doing two kinds of backups -- a Time Machine backup (which is an incremental backup that keeps a full copy of your entire system) and a disk clone backup (which clones the main disk so the system can be booted from the clone in cases of emergency).
   An incremental backup takes quite a bit of time to restore. In my experience with Time Machine, restoring took all day. The restored system wasn't quite all there, so I had to manually fix things that were missed. (And I still don't know why they were ignored in the TM backup.) No real complaints, though; I got my system back, and I was immensely relieved.
   But a cloned drive is a good thing to have in addition to an incremental backup. On the Mac, you can instantly boot up from the clone (I'm not exaggerating; choosing the clone as the boot drive takes a second or so) and be back to work no matter what's happened to your primary disk. (This is one of my many reasons Macs just plain work out better in daily use.)
   And restoring your primary disk drive from the cloned drive takes less than an hour if your drives are really huge, or a little less for normal-size drives.
   I realize there are excellent backup programs for Windows, so my advice holds for Windows backups as well. Make it easy on yourself and use an incremental backup program for the occasional slip-up in which you need to get a file back instantly, or for those times when you realize an earlier version of a file was actually the one you needed to save instead of the current one. (Time Machine makes this sort of thing fun, and I'm not kidding.) But make a daily clone to protect yourself from massive failure.