Why is “Android OS” uploading so much data?

Question

After switching from my Nexus S to a Nexus 4 I noticed that my phone was transferring huge amounts of background data. Like 70 MB in 15 minutes. As my data plan only allows 300 MB per month I was not amused. Even when connected to WiFi, it often (but not always!) was uploading tons of data.

According to the "Network Usage" the culprit was "Android OS". So I tried to limit the background data of it only to find that "Android OS" seems to be the only "app" which doesn't offer this option. Great. :-( Well okay, that's what firewalls apps are made for. :-) I configured AFWall+ but that only cured the symptom not the cause.

Next I redirected the traffic to a laptop with a Wifi card and used the usual tools (tcpdump, wireshark) to analyse the traffic. Result: many many uploads to some Google servers but SSL encrypted so no chance to see the contents.

I kept investigating and found this very interesting article: http://socialtimes.com/tracking-down-android-data-usage_b48336 Apparently Google has began expanding its cloud-based backups of the phone settings so that it now also does backups of the data of some apps. So, I turned off "Back up my settings" in the Privacy settings and whoopiedoo, the sending stopped and the data traffic returned to a normal amount!

There is a post in a Google forum with similar experience: Something within the Android System—maybe Backup—is using up all my data allowance.

I started looking in the Android documentation and found that there is such a thing as "Android Backup Service" which apps can use to backup their application data to the Google cloud: http://developer.android.com/guide/topics/data/backup.html

And there is even an CLI utility "bmgr" to interact with the Backup Manager.

But I cannot find any information about how the phone owner can find out which application is backing up which data. And how to influence or stop this. I'd be happy to use the backup service—it saved me a lot of time when switching to my new phone—but the way it is implemented now it's definitely unusable.

After talking to my former coworker and Android expert Izzy who was clueless too, I decided to post this issue here as—like he said—I will find the best experts here. Well, let me know if you have any idea about this. Any hint is welcome!

Answer 1

The list of applications with backups as well as how much space each backup uses is on your Google Account Dashboard under "Android Devices".

Unfortunately, there isn't, I believe, any way to control it other than turning it on or off entirely.

Answer 2

@David Silva Smith : You are saying that I should answer my own question? Okay, looking at the comments there is actually more technical information in my question than in any of the answers. :-)

The (currently) final answer seems to be that Google doesn't allow us more insight and no way to influence the backed up data. This is inacceptable but how can we change Google's behaviour???

Andy

PS:
It's true that the Google Dashboard shows a little more detail about the saved data. BUT: it takes a day or two for the information to appear AND it's definitely not complete. I reactivated the cloud backup feature about a week ago, it has uploaded 178 MB of data, but the dashboard shows just this:

Android Wallpaper 05.03.2013 10:52 6,6 MB
Android System Settings 05.03.2013 02:16 3,61 KB
Android Market 03.03.2013 13:27 16 B
AndroRadio 03.03.2013 13:27 8 B

That's wrong AND not useful. sigh

Answer 3

I would propose to disable the Android built-in Google Cloud Backup in the settings and use another app to backup your phone.

For example, Carbon supports backing up apps online to different cloud storage providers, and allows to restrict backups to times when you're connected with a Wifi network. Carbon also has the advantage that it can backup apps that are not backed up by Google Cloud Backup.

TitaniumBackup also supports backing up your data online, but requires root.

Both apps also support that they only back-up when your phone is connected to a charger, so that they don't suck your battery empty when you need it for other purposes.

The disadvantage of this solution would be that they both only support scheduled backups, so if you back-up only once a week, you might lose a week of your backed up data if you lose or destroy your phone just before the backup would run. However, I don't know exactly which schedule is used by the Google Backup solution, so this could suffer a similar problem.