How do I stop Time Machine from backing up Aperture thumbnails?

Question

Hi,
My 2TB backup drive recently became full, and I became curious as to what was filling it up. I wrote a perl script to analyze the Time Machine backups, and I noticed that over 50% of my backup was filled with AP.Thumbnails and AP.Minis from the Aperture project directory. In particular, the AP.Thumbnails files in the backup consumed 737 GB of disk space!
The problem with the thumbnails files is that they are a single file that contains all of the thumbnails for all of the 40,000 photos I have in Aperture and it is now 20gb in size. Every time I add a new file to Aperture, the thumbnail file changes, and I get a new 20gb of data added to my backup. I add photos often which means that most of my backups have 20gb of Aperture files (which are easy to rebuild and don't need to be backed up).
I decided to try and stop Time Machine from backing up these files, and there seems to be no way of doing so (without telling Time Machine to skip backing up my entire Aperture project which I don't want to do). In Finder, you can do a "show package contents", but the Time Machine GUI doesn't allow this.
I tried to tell Time Machine to exclude the files via the GUI, but Time Machine sees the Aperture Library as a single package and won't let me exclude individual files from within the package.
I googled around, and found the attribute that Time Machine puts on files to exclude them from the backup. I used xattr to set the attributes:
xattr -w com.apple.metadata:comapple_backupexcludeItem com.apple.backupd <filename>
I also used this command on the iPhoto thumbnail files.
I used spotlight to find all of the files with this attribute using this command:
sudo mdfind "comapple_backupexcludeItem = 'com.apple.backupd'"
This command returned the iPhoto files, but did not return the Aperture files.
However, if I run "xattr" on the Aperture files, the attribute does exist!
During my next time machine backup, the iPhoto files were skipped as I wanted them to be, but the Aperture thumbnails were backed up again
I thought that maybe time machine was looking at the aperture package as an atomic unit, but iPhoto is stored as a package as well, and the attributes worked there on files inside the package.
Does anyone have any idea why time machine is still backing up these files? Is there any way I can get around this?
It seems to me to be an incredible oversight on Apple's part since both tools are Apple. The thumbnails files are very expensive to backup, and they are not necessary for backup since the are easy to rebuild from the original photos which are also backed up.
Thanks,
Ron

Answer 1

Shadow99999 wrote:
Hi,
My 2TB backup drive recently became full, and I became curious as to what was filling it up. I wrote a perl script to analyze the Time Machine backups,
No need to write your own script for that. there are a couple of already made nice GUI tools for this - TimeTracker http://www.charlessoft.com/ and BackupLoupe http://soma-zone.com/BackupLoupe/
and I noticed that over 50% of my backup was filled with AP.Thumbnails and AP.Minis from the Aperture project directory. In particular, the AP.Thumbnails files in the backup consumed 737 GB of disk space!
The problem with the thumbnails files is that they are a single file that contains all of the thumbnails for all of the 40,000 photos I have in Aperture and it is now 20gb in size. Every time I add a new file to Aperture, the thumbnail file changes, and I get a new 20gb of data added to my backup. I add photos often which means that most of my backups have 20gb of Aperture files (which are easy to rebuild and don't need to be backed up).
I decided to try and stop Time Machine from backing up these files, and there seems to be no way of doing so (without telling Time Machine to skip backing up my entire Aperture project which I don't want to do). In Finder, you can do a "show package contents", but the Time Machine GUI doesn't allow this.
I tried to tell Time Machine to exclude the files via the GUI, but Time Machine sees the Aperture Library as a single package and won't let me exclude individual files from within the package.
I don't have aperture but I think most people exclude the whole thing from TM backups and back it up separately. but if you want to exclude a subfolder in a package that's easy too. just select the package in finder, control-click on it and select "show package contents". in the resulting finder window drill to the folder you want to exclude and drag it to the TM exclusion list in TM system preferences->options.
I googled around, and found the attribute that Time Machine puts on files to exclude them from the backup. I used xattr to set the attributes:
xattr -w com.apple.metadata:comapple_backupexcludeItem com.apple.backupd <filename>
I was not aware of this method for excluding stuff from TM backups. could you provide a link to where you found this?
I also used this command on the iPhoto thumbnail files.
I used spotlight to find all of the files with this attribute using this command:
sudo mdfind "comapple_backupexcludeItem = 'com.apple.backupd'"
This command returned the iPhoto files, but did not return the Aperture files.
that's because Spotlight never looks inside packages unless you start a search inside a package directly. iphoto seems to be the only exception. I don't know how it's done.