What I Learned about Time Machine backups from timedog

I love Time Machine. For years and years backups were something I was supposed to do, but never found the time to do. Backups were difficult, you had to purchase backup software, find a drive, set them up, and then either manually execute your backup (which is what I did for years) or figure out how to automate them.

Enter Time Machine

With the launch of Mac OS X 10.5 (“Leopard”), Apple included this brand new Backup system. But, this article isn’t about Time Machine. Perhaps I’ll do one of those at some point. This article is about what I just learned about TIme Machine. I’m backing up a lot of stuff I shouldn’t be…

As I’m writing this article, Time Machine is up in my Menu Bar happily spinning. When I click on it, this is what it says:

[![](http://res.cloudinary.com/robpickering/image/upload/h_139,w_300/v1480171698/TMPreparing_i1hgo8.png "TMPreparing")](https://robpickering.com/wp-content/uploads/2011/02/TMPreparing.png)Time Machine Preparing Backup
After a few minutes, that menu changes to this:
[![](http://res.cloudinary.com/robpickering/image/upload/h_139,w_300/v1480171697/TMBackingup_igkc0i.png "TMBackingup")](https://robpickering.com/wp-content/uploads/2011/02/TMBackingup.png)Time Machine Backing Up
What?!? 2100 files? 920MB? What changed? What is Time Machine backing up? That’s a lot of data!

Enter timedog

timedog is a Perl script written by J.D. Smith which does an amazing job just cataloging your Time Machine backup and determining what changed. The benefit here is that you can find stuff that’s being backed up, that you don’t really want backed up, and then exclude those items from your Time Machine backup.

I’m going to show you how to run the script, then how to interpret the results, and finally how to customize Time Machine to stop backing up things that you really don’t care about, which will give you more storage room to backup the things you do.

Running timedog

The first step is to download and install the Perl script. You can get timedog here.
I cannot really improve on the official instructions for running timedog, so here they are from the official site:

Usage

  1. Open Terminal (in /Applications/Utilities)
  2. cd /Volumes/Time Machine/Backups.backupdb/[Computer Name]
  • Note Time Machine may be different on your system.
  • Replace [Computer Name] with the name of your computer (see System Preferences => Sharing).
  1. /path/to/timedog -d 5 -l
  • For instance, if you unzipped timedog to your Desktop, the path would be ~/Desktop/timedog

The example above uses the options -d 5 -l which will summarize the changes up to five directory levels deep, and hide rows that pertain to symbolic links. These links are often meaningless and can safely be ignored.

Once you’ve run the script on your Time Machine backup directory, you’ll get output similar to the following (this is mine from earlier today):

[bash collapse=”false” gutter=”false”]
Walkabout:Walkabout pickerin$ timedog -d 5 -l
==> Comparing TM backup 2011-02-25-090631 to 2011-02-24-154335
Depth: 5 directories
2.9KB-> 3.3KB /.Backup.log
0B-> 527B /.com.apple.TMCheckpoint
1.9KB-> 1.9KB /.exclusions.plist
182B-> 182B /Macintosh HD/Applications/World of Warcraft/WoW.mfil
306.1KB-> 499.8KB [5] /Macintosh HD/Applications/World of Warcraft/Cache/ADB/
193.1KB-> 380.9KB [8] /Macintosh HD/Applications/World of Warcraft/Cache/WDB/
578B-> 578B [2] /Macintosh HD/Applications/World of Warcraft/Data/enUS/
408B-> 408B [1] /Macintosh HD/Applications/World of Warcraft/Data/Interface/
15.9MB-> 16.1MB [1195] /Macintosh HD/Applications/World of Warcraft/Interface/AddOns/
1.8KB-> 4.2KB /Macintosh HD/Applications/World of Warcraft/Logs/connection.log
17.7KB-> 17.7KB /Macintosh HD/Applications/World of Warcraft/Logs/FrameXML.log
450B-> 450B /Macintosh HD/Applications/World of Warcraft/Logs/GlueXML.log
2.6KB-> 2.6KB /Macintosh HD/Applications/World of Warcraft/Logs/gx.log
27.3KB-> 28.1KB /Macintosh HD/Applications/World of Warcraft/Logs/Launcher.log
2.9KB-> 5.8KB /Macintosh HD/Applications/World of Warcraft/Logs/Sound.log
52.7KB-> 58.9KB [6] /Macintosh HD/Applications/World of Warcraft/Logs/
1.6KB-> 1.6KB /Macintosh HD/Applications/World of Warcraft/WTF/Config.wtf
494B-> 493B /Macintosh HD/Applications/World of Warcraft/WTF/Launcher.WTF
24.8MB-> 24.6MB [180] /Macintosh HD/Applications/World of Warcraft/WTF/Account/
13.0KB-> 13.0KB /Macintosh HD/Users/pickerin/.bash_history
50.5MB-> 50.5MB /Macintosh HD/Users/pickerin/.dropbox/dropbox.db
50.5MB-> 50.5MB [1] /Macintosh HD/Users/pickerin/.dropbox/
24.0KB-> 24.0KB /Macintosh HD/Users/pickerin/Desktop/.DS_Store
…. -> 24.4MB /Macintosh HD/Users/pickerin/Desktop/WCS7_0cg.pdf
24.0KB-> 24.4MB [2] /Macintosh HD/Users/pickerin/Desktop/
87.2KB-> 87.2KB [8] /Macintosh HD/Users/pickerin/Documents/Dropbox/
285.6MB-> 286.8MB [41005] /Macintosh HD/Users/pickerin/Documents/Microsoft User Data/
77.6MB-> 78.9MB [89] /Macintosh HD/Users/pickerin/Library/Application Support/
29.4KB-> 51.5MB [129] /Macintosh HD/Users/pickerin/Library/Arq/
3.8MB-> 3.8MB [1] /Macintosh HD/Users/pickerin/Library/Cookies/
425B-> 425B [1] /Macintosh HD/Users/pickerin/Library/LaunchAgents/
1.3MB-> 1.8MB [135] /Macintosh HD/Users/pickerin/Library/Mail/
5.9MB-> 5.9MB [57] /Macintosh HD/Users/pickerin/Library/Preferences/
1.5MB-> 1.5MB [11] /Macintosh HD/Users/pickerin/Library/Safari/
4.2MB-> 289.0MB [21] /Macintosh HD/Users/pickerin/Music/iTunes/
==> Total Backup: 42898 changed files/directories, 835.86MB
[/bash]

Wow, that’s a lot of changed files. Yes, I play World of Warcraft. However, as I look through the output of timedog, I immediately see some files I really don’t need to backup:

  • /Macintosh HD/Applications/World of Warcraft/Interface/AddOns/ — 307MB (AddOns are updated a lot and can be re-downloaded)
  • /Macintosh HD/Applications/World of Warcraft/Data/ — 26GB (this directory is the bulk of the App and changes with patches)
  • /Macintosh HD/Users/pickerin/Documents/Microsoft User Data/ — 3GB (really don’t need these backed up in my use of Outlook)
  • /Macintosh HD/Users/pickerin/Documents/Dropbox/ — 1.1GB (Dropbox is stored at Dropbox, I don’t need to back it up)
  • /Macintosh HD/Users/pickerin/Library/Arq/ — 27GB (Arq is an online backup tool, the Caches.noindex directory is all of this)

So, these files amount to around 57.5GB of storage on disk. That means 57GB of my Time Machine disk, assuming they’re only backed up once. So, let’s configure Time Machine to stop backing those up.

Configure Time Machine Exclusions

To exclude items from your Time Machine backup, first run the Time Machine Preference Pane from System Preferences, then click the Options… button.

[![](http://res.cloudinary.com/robpickering/image/upload/h_210,w_300/v1480171697/TimeMachineOptions_q5r0ua.png "TimeMachineOptions")](https://robpickering.com/wp-content/uploads/2011/02/TimeMachineOptions.png)Time Machine Preference Pane
Now, click the small plus sign ( + ) in the lower left corner and begin selecting the directories / files you wish to exclude from your backups. Here’s a screen shot of mine after I added the above directories (I also had previously set my Time Machine to exclude my Virtual Machine directory):
[![](http://res.cloudinary.com/robpickering/image/upload/h_237,w_300/v1480171696/TimeMachineExclude_xbri6k.png "TimeMachineExclude")](https://robpickering.com/wp-content/uploads/2011/02/TimeMachineExclude.png)Time Machine Exclusions
When you’re done adding directories/files, just click the **Done** button. Your next backup will exclude these files, I’m not sure if that means it will delete the files already in your Time Machine backups, or if it will just stop backing them up going forward. I’ll check my backup drive the next time it runs and let you know. At least they won’t be taking up space going forward! Confirmed: Once you choose to exclude items from your Time Machine Backup, Time Machine will remove them from **ALL VERSIONS** of your backups, so they will be completely removed from your Time Machine backup volume.
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