http://tidbits.com/ Bootable duplicates are an important part of a complete backup strategy. But when you have to boot a Mac from such a disk — even if only temporarily — things may not always behave as you expect. Joe Kissell sheds light on some of the common points of pain and confusion when starting a Mac from a duplicate. en-us Copyright 2013 TidBITS Publishing Inc. Sat, 23 Mar 2013 00:00:00 EDT Sat, 23 Mar 2013 00:00:00 EDT editors@tidbits.com (TidBITS Editors) editors@tidbits.com (TidBITS Editors) http://tidbits.com/images/tb_logo_152x55.png http://tidbits.com/ 55 152 TidBITS badge http://db.tidbits.com/article/13618?rss#comments_18088 Sat, 23 Mar 2013 08:43:19 EDT http://tidbits.com/article/13618#comments_18088
Joe]]> http://db.tidbits.com/article/13618?rss#comments_18086 Sat, 23 Mar 2013 08:08:31 EDT http://tidbits.com/article/13618#comments_18086
I notice that the problems you allude to with having different names for the source volume and the duplicate are to do with using the latter as a “permanent” substitute for the former. I haven’t had to do this, but I guess I would have to rename the duplicate then, in line with your recommendation.

I like having a different name for the duplicate when I’m using it “temporarily”, though. For one thing, I can see clearly which disc is which in the Finder. How about it, if I start to use the duplicate “permanently”, then I change the name to “Macintosh HD” and the name of my source disc to “Macintosh HD OLD”. Wouldn’t that give me the best of both worlds? Would I have other problems?]]> http://db.tidbits.com/article/13618?rss#comments_18021 Tue, 19 Mar 2013 18:05:53 EDT http://tidbits.com/article/13618#comments_18021
As for Dropbox, yes, what you describe can happen, because Dropbox checks some of those unique hardware identifiers. However, once you log in with the same account and password, everything quickly returns to normal.

Joe]]> http://db.tidbits.com/article/13618?rss#comments_18020 Tue, 19 Mar 2013 18:02:18 EDT http://tidbits.com/article/13618#comments_18020 The result was the new hard drive somehow had 70,000 fewer files than the old one. I also find that booting from a cloned drive makes some programs (Dropbox for one) think you are on another computer so there is reauthentication to be done.]]> http://db.tidbits.com/article/13618?rss#comments_18015 Tue, 19 Mar 2013 15:06:54 EDT http://tidbits.com/article/13618#comments_18015
Joe]]> http://db.tidbits.com/article/13618?rss#comments_18014 Tue, 19 Mar 2013 15:00:16 EDT http://tidbits.com/article/13618#comments_18014 http://db.tidbits.com/article/13618?rss#comments_18011 Tue, 19 Mar 2013 13:14:57 EDT http://tidbits.com/article/13618#comments_18011
Joe]]> http://db.tidbits.com/article/13618?rss#comments_18008 Tue, 19 Mar 2013 10:44:02 EDT http://tidbits.com/article/13618#comments_18008
One idea that might deserve mention: store your bootable clones as disk images on a big external drive. Then you can keep several of them in case the most recent one has inherited a problem from your boot drive.

I presume this would work: pick the clone image you want to boot from, and expand it to a separate partition on the external drive. Then you should be able to boot that partition.]]> http://db.tidbits.com/article/13618?rss#comments_18005 Tue, 19 Mar 2013 08:28:54 EDT http://tidbits.com/article/13618#comments_18005 http://db.tidbits.com/article/13618?rss#comments_17994 Tue, 19 Mar 2013 00:36:04 EDT http://tidbits.com/article/13618#comments_17994 http://db.tidbits.com/article/13618?rss#comments_17992 Mon, 18 Mar 2013 19:33:20 EDT http://tidbits.com/article/13618#comments_17992
Joe]]> http://db.tidbits.com/article/13618?rss#comments_17991 Mon, 18 Mar 2013 19:06:48 EDT http://tidbits.com/article/13618#comments_17991
For this reason, I use SuperDuper! to maintain my clones and Time Machine for more frequent backups. This way I can update my clones less often (say once a week) and still be sure I have access to all my files should something go wrong in the meantime.

The reverse case arises for those who don't back up before making important modifications to their system, like major software and system updates. If your system is not in the best possible shape, an update can fail and even put your system out of commission. Without a recent backup, you're SOL. In this case, a clone is more practical than Time Machine because, as is the theme of this article, you can boot from the backup immediately and get back to work. Restoring from a Time Machine backup when your boot drive is hosed is time consuming and, I've found, not always reliable. Reinstalling over the network will put you even more behind the eight ball. In addition, if you cannot use your system because the drive itself has failed, you won't be able to access the Recovery HD partition either, which will mean even more work before you can return to work (or play). While a cloned backup won't include the Recovery HD partition, it will keep you going while you either reformat and reinstall OS X on your original drive - or replace the drive.

Another way around the clone frequency issue would be to use one backup drive for daily updates and another drive to update once a week or so, which would likely be the case if you follow Joe's advice to keep a copy of your boot drive off site. You're not going to update an off-site drive twice a day.

I will add my two cents here that while cloud backups may be convenient in some ways, they may be no more reliable than your own in-house backups. Cloud backups are, after all, done on someone else's computer, one likely to be even more heavily used than your own. Cloud providers not infrequently suffer service outages and hardware failures as well. And restoring from the cloud, even if it's possible, will be agonizingly slow. And who can afford to pay for the volume of cloud storage that would be required to back up an entire system? Cloud storage may be great for collaboration or those who use more than one computer - but for archival purposes I think the drawbacks are prohibitive.]]> http://db.tidbits.com/article/13618?rss#comments_17917 Thu, 14 Mar 2013 10:54:08 EDT http://tidbits.com/article/13618#comments_17917
The short version is this: If you create an alias—and that's essentially what you're doing with Sidebar items and Login items too—to an item on the volume from which you have booted, that alias is a relative location. That is, it says, "On the current startup volume, whatever that happens to be, follow this path to get to this file or folder." However, if you create an alias to something on another volume, you get an absolute path: "On this particular volume name, follow this path to get to this file or folder."

Usually, this arrangement produces exactly the desired result: when you boot from your duplicate, your aliases point to things on the duplicate, not on your original volume. But there are some edge cases where it doesn't, and the problem is that it's not always visually obvious where an alias's target is, when you have two identical volumes mounted. So if you want to be absolutely safe and certain, you always navigate from the top of the desired volume to the item you want. (Because remember, sometimes you may WANT to open something on the non-boot volume, although most of the time you won't.)]]> http://db.tidbits.com/article/13618?rss#comments_17916 Thu, 14 Mar 2013 07:04:17 EDT http://tidbits.com/article/13618#comments_17916 http://db.tidbits.com/article/13618?rss#comments_17913 Thu, 14 Mar 2013 00:13:18 EDT http://tidbits.com/article/13618#comments_17913 http://db.tidbits.com/article/13618?rss#comments_17911 Wed, 13 Mar 2013 19:24:40 EDT http://tidbits.com/article/13618#comments_17911 http://db.tidbits.com/article/13618?rss#comments_17905 Wed, 13 Mar 2013 15:47:34 EDT http://tidbits.com/article/13618#comments_17905
If an app on the normal internal boot drive is acting up, and you boot from your clone to see if the app is ok there, you must be sure to NOT use the sidebar or any similar shortcut to open the app.

You must go into the "Appications" folder on the clone, and then open the app from there.

It's easy to forget. After years of working wih clones, I still sometimes do it.]]>