Why are iTunes backups so darned big?

Discussion in 'iOS 10' started by zorinlynx, Jan 29, 2017.

  1. zorinlynx macrumors 601

    zorinlynx

    Joined:
    May 31, 2007
    Location:
    Florida, USA
    #1
    I just did an iTunes backup of my phone and it took forever (about 20 minutes). I found the backup in the MobileSync directory and it's a colossal 33GB.

    Meanwhile, my iCloud backup of the same phone is only using 4.2GB.

    Does anyone know what could be accounting for the extra 29GB or so? I don't have anything excluded from my iCloud backup, and while I'd expect a difference of a few % between the sizes due to differing storage methods and such, a factor of seven is a bit too much to ignore.
     
  2. Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #2
    My iCloud backup for my Air 2 is 100MB and my iTunes backup is 900MB. I have dissected the backup with some backup explorer application and found the root of my problem. I sync about 2GB of photos via iTunes. The iTunes backup create a thumbnail for each photo and stores it. Maybe incase you can't resync those photos via iTunes after real tiring your device. Not sure. But the 2GB of photos equaled about 750MB of thumbnails. The other 150MB was just system stuff.
     
  3. zorinlynx thread starter macrumors 601

    zorinlynx

    Joined:
    May 31, 2007
    Location:
    Florida, USA
    #3
    Interesting, so it may be backing up my photos, despite the fact that they should be considered purgeable data because they're in iCloud Photo Library and I have optimized storage on? Talk about wasteful. I already have those photos backed up on my Mac, in Time Machine, on my own personal offsite backup system AND in iCloud. I don't need yet ANOTHER backup of my photos, one which isn't complete anyway.

    Damnit Apple.
     
  4. Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #4
    I don't know if any iOS 10 backup explorers exist. Last time I checked was iOS 9. But iBackupbot may help you to double check.
     
  5. akash.nu macrumors 68020

    akash.nu

    Joined:
    May 26, 2016
    #5
    Generally the items on iTunes backup are more detailed than iCloud backup. Because it's assumed that you are more likely to restore from iTunes backup when you may not have data connection. In such scenario iCloud backup won't work.

    Eg. iCloud backup doesn't actually backup your apps but iTunes backup do.
     
  6. Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #6
    iTunes backup does not back up your apps. Only the app data. Just like iCloud backup.
     
  7. akash.nu macrumors 68020

    akash.nu

    Joined:
    May 26, 2016
    #7
    It does backup the apps as well. That's why you get the notification "There are apps on your iPhone which are not in your iTunes library "
     
  8. KALLT macrumors 601

    Joined:
    Sep 23, 2008
    #8
    It has never backed up apps. In the past, iTunes could also transfer purchases (apps, music, etc.) from your iPhone to your library before making the backup. It did that automatically during the syncing process. It does not do that anymore since iOS 9, at least for apps. iTunes does not back up data that either originates from your iTunes library or the iTunes Store. Apps that aren’t located in your library when you restore an iPhone will just not be restored, but the apps’ data will still be transferred, allowing you to download the app from the App Store and using it with the existing data.
     
  9. Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #9
    Because if you don't have the app in your iTunes library, the app cannot be reinstalled on the device after you restore, and the app data that is saved in the backup cannot be restored. Only the app data is backed up, not the app itself. Otherwise my iTunes backup would be 50GB+. Not 900MB.
     
  10. akash.nu macrumors 68020

    akash.nu

    Joined:
    May 26, 2016
    #10
    That actually could be dependent on other options you've chosen. There's a specific tick to choose if you'd want to backup your apps. It's unticked for me as well. The app as a whole get backed up if that option is ticked and that's why you can install the apps even if you don't have connection to internet when you restore from backup. I've seen the app binary files within system files. They physically get copied. That's how iTunes backup works.
     
  11. Mlrollin91, Jan 29, 2017
    Last edited: Jan 29, 2017

    Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #11
    I have literally no idea what you are talking about. There is no option in iTunes to backup the app to the actually backup, only the data. Please provide proof of your statement, because I've been doing this for 10 years now and what you describe has never been the case. The reason why you can install the app with no internet connection is because the app is physically saved on your computer, in your iTunes library. Has nothing to do with backups.

    https://www.quora.com/Does-iTunes-backup-the-entire-iPhone-OS-or-only-the-apps
    https://discussions.apple.com/thread/4464810?start=0&tstart=0
    https://support.apple.com/en-us/HT204136

    Directly from Apple.com

    iTunes backups
    From your Mac or PC, you can make a backup of your device in iTunes. Syncing your device with your computer isn't the same as making a backup. An iTunes backup includes nearly all of your device's data and settings. An iTunes backup doesn't include:
    • Content from the iTunes and App Stores, or PDFs downloaded directly to iBooks (You can back up this content using Transfer Purchases in iTunes.)
     
  12. akash.nu macrumors 68020

    akash.nu

    Joined:
    May 26, 2016
    #12
    Yes the apps are stored in the library. I see what you mean. Apologies, yes you're right. It was 3 in the morning. I wasn't thinking straight.
     
  13. Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #13
    No worries, no need to apologize. I was just very confused.
     

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