Time Machine backup smaller than hard drive

Hi,


My Time Machine external hard drive became full so I dediced to erase it and start from scratch. I set it all up and it was going to take 4 hours to backup 300GB of data, which is the amount of space taken up on my internal HD. When I came back to my Mac a couple of hours later it had finished the backup but it only seems to be 160GB in size?! Is this something to be concerned about, I assumed the Time Machine backup would be the same size as the data currently occupying my internal HD.


Thanks.

MacBook Pro with Retina display, Mac OS X (10.7.4), 2.6GHz, 8GB Ram, 512GB, 1GB NVIDIA

Posted on Jul 28, 2013 3:20 PM

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6 replies

Jul 28, 2013 3:40 PM in response to TJ Skywasher

The portable Mac's also have TimeMachine local backups so on your boot drive there might be duplicates in the hidden tmbackup file.


You can disable the local backup file (search online) and or just forget TimeMachine and trust a old reliable and non-lying bootable clone which you can boot and verify it's contents are exactly as intended.


Most commonly used backup methods

Jul 28, 2013 5:26 PM in response to TJ Skywasher

In the sidebar of a Finder window, select the icon representing your startup volume ("Macintosh HD," unless you gave it a different name.) At the top level of the volume are folders with these names, among others:

  • Applications
  • Library
  • System

Enter Time Machine and select the most recent snapshot, which is behind the frontmost window. Are those folders present in the snapshot?

Jul 29, 2013 7:04 AM in response to TJ Skywasher

Triple-click anywhere in the line below on this page to select it:

tmutil compare | open -f -a TextEdit

Copy the selected text to the Clipboard (command-C).


Launch the Terminal application in any of the following ways:


☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)


☞ In the Finder, select Go Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.


☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.


Paste into the Terminal window (command-V).


The command may take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear.


A TextEdit window will open with the output of the command. Each line that begins with a plus sign (“+”) represents a file that has been added to the source volume since the last snapshot was taken. These files have not been backed up yet.


Each line that begins with an exclamation point (“!”) represents a file that has changed on the source volume. These files have been backed up, but not in their present state.


Each line that begins with a minus sign (“-“) represents a file that has been removed from the source volume.


Files that you’ve excluded from backup, or that are excluded automatically, are ignored.


At the end of the output, you’ll get some lines like the following:


-------------------------------------

Added:

Removed:

Changed:


These lines show the total amount of data added, removed, or changed on the source(s) since the last snapshot.

Jul 29, 2013 7:48 AM in response to Linc Davis

I'll give that a go thanks. I've been doing some quick looking around the Time Machine backup and cross referencing with data on my HD and I think I may be able to account for most of the missing data.


At the moment my HD is 200GB full, I had a bit of a clean out last night and my latest Time Machine Backup size was 135GB. It did report that 280GB would be backed up but 80GB of that is classed as Backups in About this Mac. It would appear that some of the 65GB discrpancy might have something to do with Final Cut Pro. I have an Events folder which is just over 20GB in size and a Projects folder thats between 40-50GB, it's the Projects folder that seems to only be a few MB's on the Time Machine backup. I'm assuming it doesn't need to transfer over the Project data only the Event data? If so that would account for most of the missing data and I guess there's also some other things that TM doesn't need to copy over from elsewhere in the system.

Jul 29, 2013 8:29 AM in response to TJ Skywasher

I'm assuming it doesn't need to transfer over the Project data only the Event data?


No, all the data should be backed up. TM won't back up files that are open for writing, so you should quit the application that opens them sometimes to allow them to be copied. If that doesn't have an effect, post details.


It was pointed out earlier that local snapshots are not backed up at all, so don't include them in your estimate of how much data should be copied.

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Time Machine backup smaller than hard drive

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