Time Machine Backup question

[Gotenks98]

I wanted to know would it be possible to do the following backup situation. We sometimes assist students with backing up their files and often times they can not boot into their Mac but they can boot off of another drive that has an install on it from USB. What I wanted to do is plug in a second USB HD and do a time machine backup of the drive thats not being currently booted. Is there a way to specify a different OSX install to back up than the one currently running?

[bdsams Veteran]

not 100% sure, but I don't think you can boot a time machine backup.

[Karl L.]

I don't think that backing up a broken OS X installation is going to help you much anyway, even if Time Machine can target another partition. You can, however, backup the /Applications and /Users folders to another HFS+ partition, reinstall OS X, then restore the folders. You'll need to make sure you set the permissions correctly once you restore them, though. In particular, make sure you chown the contents of each user folder once you restore it. You could also try an archive install or some other repair technique. Since you have a complete backup of the user's data, there is no chance of data loss at that point.

[Gotenks98]

I don't think that backing up a broken OS X installation is going to help you much anyway, even if Time Machine can target another partition. You can, however, backup the /Applications and /Users folders to another HFS+ partition, reinstall OS X, then restore the folders. You'll need to make sure you set the permissions correctly once you restore them, though. In particular, make sure you chown the contents of each user folder once you restore it. You could also try an archive install or some other repair technique. Since you have a complete backup of the user's data, there is no chance of data loss at that point.

This is exactly what I am looking for. Do I specify in time machine which folders to grab (I thought it was only for excluding folders) or do I just do a copy paste of those folders?

[Karl L.]

You shouldn't use Time Machine at all in this case. Open a terminal and type cp -a /Volumes/Macintosh\ HD/Applications /Volumes/Macintosh\ HD/Applications /Volumes/My\ External\ Disk/2013\-01\-18\ customer\'s\ name/, assuming that the partition you want to backup is called "Macintosh HD", the back partition is called "My External Disk", and the "2013-01-18 customer's name" folder already exists. The -a switch tells cp to preserve attributes, permissions, etc. That's also why you need to copy the data to another HFS+ parition: you will lose all that extended information if you do not.

When you want to restore the data, use cp -a /Volumes/My\ External\ Disk/2013\-01\-18\ customer\'s\ name/Applications/* /Applications/ from a terminal in the new installation to restore applications,and cp -a /Volumes/My\ External\ Disk/2013\-01\-18\ customer\'s\ name/Users/Some\ User\ Name/* /Users/Some\ New\ User/ for each user on the system you want to restore. (You must have created the user accounts in OS X already by this point. Restoring just the folder to /Users won't do much good by itself.) Then run chown -R somenewuser:staff /Users/Some\ New\ User/ for each of the user directories you just restored to set the permissions right.