High data usage since updating to 8.1.1

No increase in data usage for me. If you monitor Settings > Cellular > Use Cellular Data For (including tapping to see the details of System Service at the bottom of that section) it should help you identify what it is that is using the data and that is the first step toward knowing what to do about it.

I just did an internet search for "how many mb per minute does Facebook use" and came up with the following that estimates 1 to 2 MB per minute so if that is reasonably accurate, 13.8 MB for 10 minutes seems about right. I've seen absolutely no increase in usage due to iOS 8. I can only suggest you keep an eye on Settings > Cellular to watch where the data is going.

I am seeing the same thing with 8.1.1. In Settings, Cellular, System Services, Documents & Data is the data hog now. Following some other threads I turned off WiFi and watched the Documents and data usage go from 65.4 to 79.3 in like 15 min. I am all ready more than halfway through my very limited data amount for the month ending 12/27. I have turned cellular data off for now. Anyone hit upon a solution please let us know. I all ready have very restrictive data usage settings and even disabled iCloud Drive even though the Cellular Data setting was off however that had no effect on the data drain. I also disabled Photo stream but also no effect on the drain.

Not a permanent solution but if you log out of iCloud the data drain seems to stop. I even tried logging back in again and the drain started right back up. I did find another article that mentioned logging out of iCloud on older non Yosemite devices as a possible fix.

Here is another thread that is basically the same as this one.

Cellular data drain (iOS 8.1.1) with "Documents & Sync"

The very last entry on this post is the person talking about logging out of iCloud on older devices.

IOS 8 High Cellular Data Usage

Based on the suggestion of Walter from another post I have been testing and testing this. At this point I seem to have gotten the data drain under control at least for the last 40 min or so I am not seeing the drain. In my situation I had verified the problem was specific to iCloud. I had eliminated the data drain by logging out of iCloud, however that of course, wasn't a permanent solution. I started modifying settings for iCloud drive on my computers that were connected to my account. First I logged out of iCloud from a couple older Macs. I did not see any immediate change in the data drain. I then disabled iCloud Drive on my Yosemite Mac and pretty immediately the data drain stopped. I then re-enabled iCloud Drive again and the drain started right back up again. I then started looking at what items are used for iCloud Drive and manually turned off all but Text Edit. Again the drain stopped. I re-enabled only the services I actually use with iCloud Drive at this point I have Preview, TextEdit, Pages and Numbers enabled and have not had any more Documents & Sync data usage over 175 KB that it initially used when I turned Cellular data on the last time more than 40 min ago. I currently have two Macs both running Yosemite both with all of the above services enabled for iCloud Drive and no data drain. I also opened each of those apps and opened documents that are stored in the iCloud drive and no cellular data has been used for Documents & Sync. Hope maybe this can help someone else who is having this same issue. As I have been writing this Documents & Sync used a little more data went from 175 KB to 196 KB however is not continuing to climb. When I noticed the up from 175 to 196 I had accidentally opened a Safari page from Handoff. I wondered if there was anything to that so I did it again intentionally and it then went from 196 to 208. Still not a drain but interesting that Handoff would use any cellular data as I thought it was a bluetooth service.

While it lasted 24 hours the fix was temporary. This afternoon the data drain started again going from under 1MB of Documents & Sync to 5.3 in a matter of a few min. I disabled iCloud drive on my computers again however that did not have any affect on the data drain this time. This is a very annoying bug. Yes, signing out of iCloud then means anything you add or remove from your phone is no longer syncing to the cloud so when you get a new device it cannot automatically be downloaded to your new one. If you are backing up to a computer then you can restore your data that way. Signing out is really a temporary solution.

I haven't been able to solve the problem yet but I think I'm getting closer. I've noticed that the data drain stops when my iMac is turned off, and that the data drain on the iPhone starts immediately once the iMac is turned on!!

I turned off my iMac on Friday and had no data drain all weekend. As soon as I turned the iMac on today the iPhone "Documents & Sync" started to go crazy again. I logged out of iCloud on the iMac and the drain on the iPhone stopped! So, I don't think this is an iPhone hardware problem at all!

To me it seems it's a bug in the iCloud service. Although all the configurations on the iPhone are saying that it should not use 3G, and that it should use the WiFi, it still uses the 3G somehow for some sort of synchronisation with my iMac. This is clearly a bug as I don't have anything on my iCloud drive and I have set Calendar/Contacts and Notes to sync only on WiFi. Apple please sort this one out. For now I'm switching cellular data off on the phone when I'm working on the iMac. It's the only solution at the moment.

I had my phone replaced under warranty today at an Apple store set it up as a new device came home disabled all of the usual Data using settings and the issue was still there. I contacted Apple Support again and after 2 hours with them they are finally escalating up to Engineering so I have a call back scheduled. I will update after that.

Sorry it has taken so long to respond.

So far so good on my data usage since December 23rd. After much troubleshooting, restoring, chat conversations with Apple support and then finally having my phone replaced under warranty by Apple, I still had the problem. I knew it was related to iCloud so I started doing some testing. After all the initial troubleshooting I had done based on recommendations here and on other discussions I had ended up with my iCloud account active on two computers and one iPhone. I narrowed it down to the problem coming from my MacBook Pro, when I put my Mac Mini to sleep the data drain kept going when I would put my MBP to sleep it would stop. Then I disabled each item in iCloud one at a time and waited about 5 min in between each, re-enableing if the drain did not go away. In my case when I disabled Notes my data drain stopped. I do use Notes extensively and had quite a large number of them. I left notes off for a couple days and left both my Mac Mini and MBP running and monitored my cellular data use periodically disabling WiFi and did not have the Documents & Sync data drain. I then re-enabled notes syncing and still have yet to have the data drain. I am sure this won't be the case for everyone but it is something to look at. At the very least figure out if you have one or more offending computers constantly syncing data to iCloud causing your phone to then constantly sync.

My takeaways. I agree with many of you that this is not acceptable and if any service uses cellular data then it should have an option to disable its use. Unfortunately with so many different possible combinations of uses there is no way to test every possible one however Apple could be better about taking feedback and creating fixes. I did call AT&T and they are waiving my data overages so while I am sure if you don't call they are happy to take your money the wireless carriers do seem willing to waive it if you tell them that it is caused by a problem on the device.

Hope this can help someone else.

If under System services Push Notifications is your highest at 356KB that is really nothing. System Services lists the total usage for all items then if you go in it lists each individual item. What is your total for System Services is that the 31.1MB or is that your total cellular? Were you previously having System Services very high with Documents and Sync being the largest item? If the 31.1 is your total then what other Apps are using cellular data to account for the usage?

You said iTunes is using data do you mean iTunes Store on the Cellular menu or iTunes Accounts under System Services or something else?

Game Center if you open it while on cellular then it will use some data and you can't disable the data for it specifically since it is a system service but if it is only KB then it really isn't part of the problem.

Security Services, Voicemail, are part of the system again if it is KB then it isn't worth worrying about.

Mapping Services does get used because your device is constantly attempting to update its location again KB isn't a worry.

Push Notifications you can control through Notification center but again KB.

have you managed to resolve this yet? I have an iPhone 5c and it has been eating through data (wifi and cellular) at a rate that is unbelievable. I've searched for answers, asked Apple, asked my service provider, asked my internet provider and was getting to the point of having to switch my phone on to send a message and then switch it off again. The only advice I got was all the obvious, turn off updates, cellular, location services, etc etc. if you haven't experienced this problem for yourself then you can't actually comprehend the usage. My phone was going through 1gig of data every two hours just sitting on the table next to me and everything that could be switched of was off. I had even reset my phone as new. Once restoring from icloud backup and the second time not just in case I had backed up a glitch.

What at have I found since? Through mammoth sessions of trial and error and about 100gigs of data later...I switched "photo stream" off and have had no issues! I even nervously did a test and turned photo stream back on and it immediately started eating data at the high rate again. The stress levels in this house are gone! I feel a huge weight gone so I really hope it'll work for you too. If it does, please share it as much as possible because from reading different threads, this is a problem for a lot of people!