System folders to exclude from Time Machine backups?

AMSOS

macrumors regular
Original poster
Nov 21, 2010
179
9
After getting a new Air I simply went into the backup files on Time Machine and manually copy-pasted them into respective folders in the new computer.

I don't like to take a backup of the entire disc. If I needed to restore at some point I will manually install all the apps I have. All I want from the backup are my word files, pdf's and the like.

Pictures and films I manually copy-paste on to the external.

I have therefore excluded several folders from being automatically backed up on Time Machine (see picture).

1- Is it okay to do this? Could I face any issues with restoring data in the future?

2- Are there any important files (in the Library folder?) that I really must leave to be automatically backed up? Or, is it okay to exclude such system folders completely?

3- Once I hear back from you I will setup the external as the primary backup drive on the new computer. Will this delete the older backups?

Anything that I should be careful of while setting up this drive for the new computer?
 

Brian33

macrumors 6502a
Apr 30, 2008
757
43
USA (Virginia)
1- Is it okay to do this? Could I face any issues with restoring data in the future?
This should work as you expect. None of those folders' contents will be backed up, but you'll be able to restore any files that do get backed up. After the first backup, I'd go into the Time Machine restore screen and poke around to ensure that you are backing up everything you want.

2- Are there any important files (in the Library folder?) that I really must leave to be automatically backed up? Or, is it okay to exclude such system folders completely?
"Important" is a little vague. And there are at least three Library folders. I believe that neither /Library nor /System/Library will contain the typical files that applications create and work with, though some applications can install file in the former. Then there's ~/Library (where ~ indicates your user's home directory) -- it's hard to say if there'd be any important "user" files in there. Most apps wouldn't put your work in there, but they could.

3- Once I hear back from you I will setup the external as the primary backup drive on the new computer. Will this delete the older backups?
This is a good question. I'm assuming the "older backups" were made with Time Machine. I'm quite sure they won't get deleted, but neither do you want the new Air's files lumped in with the old backups. Since the new backup is for a wholly different computer, I'm pretty sure that TM will not try to add the new computer's files onto the old "backup set" (technically, the "machine directory").

As I understand it, the Backups.backupdb directory has one machine directory for each Mac that's backed up, and the machine directory's name is whatever you've set in SystemPreferences-->Sharing-->ComputerName. You might want to give the new computer a different name from the old one to help ensure the new systems files aren't lumped in with the old ones.


Having answered your questions, I can't help but feel like you're going down a tortuous path. I suppose you have your reasons, but it would be much simpler to let TM back up everything -- then you wouldn't have to worry that you accidentally excluded something you need to restore. But, to each his own...
 

AMSOS

macrumors regular
Original poster
Nov 21, 2010
179
9
Having answered your questions, I can't help but feel like you're going down a tortuous path. I suppose you have your reasons, but it would be much simpler to let TM back up everything -- then you wouldn't have to worry that you accidentally excluded something you need to restore. But, to each his own...
Thanks for the detailed response! I understand your concern about being selective with the backup files. The thing is I sort of picked this up growing up on Windows - try to have as much control over this as possible. That's why whenever I setup a new phone or computer, I always install apps afresh. I make sure to erase the SSD of my iPhone after the yearly upgrade and install apps afresh. Never had battery or other issues, with iPhone or Android that I used earlier.

The data obviously needs to come from the backups. It was as you said, and the external now shows backups from two computers - my older one, and my current Air.
 

velocityg4

macrumors 601
Dec 19, 2004
4,619
1,192
Georgia
2. Custom fonts in the font folder. Contacts, bookmarks, software settings (preferences) and email won't be backed up if you exclude the libraries. Which is fine if they are cloud synced.

3. No, it might ask you if you want to use the existing backup. Which you don't.