Apple’s iCloud is a multi-cloud beast

Apple device users have probably taken and stored 100 billion photos:

  • In early 2013, the number was 9 billion
  • There are 100 million iPhones in active use in 2015. If each iPhone takes 1000 pictures per year, that’s 100 billion photos in 2015 alone.
  • Photos are automatically backed up to iCloud since iOS 5

Update: This article estimates the number of active iPhones at 700 Million (March 2017). During WWDC 2017, Apple revealed that iPhone users take 1 trillion photos a year.

I’d assumed that iCloud is a massive compute and storage cloud, operated like the datacenters of Google and Amazon.

Turns out that, at least for photo storage, iCloud is actually composed of Amazon’s S3 storage service and Google’s Cloud Storage service. I serendipitously discovered this while copying some photos from my camera’s SD card to my Macbook using the native Photos app. I’d recently installed  ‘Little Snitch‘ to see why the camera light on my Macbook turns on for no reason. Little Snitch immediately alerted me that Photos was trying to connect to Amazon’s S3 and Google’s Cloud Storage:

So it looks like Apple is outsourcing iCloud storage to two different clouds. At first glance this is strange: AWS S3 promises durability of 99.999999999%, so backing up to Google gains very little reliability for a doubling of cost.

It turns out that that AWS S3 and Google Storage are used differently:

For the approximately 200 hi-res photos that I was copying from my camera’s SD card, AWS S3 stores a LOT (1.58 GB), while Google stores a measly 50 MB. So Apple is probably using Google for something else. Speculation:

AWS S3 has an SLA of 99.99%. For the cases where it is unavailable (but photos are still safe), Google can be used to store / fetch low-res versions of the Photo stream.

The Google location could also be used to store an erasure code, although from the size, it seems unlikely.

Apple charges me $2.99 per month (reduced from $3.99 per month last fall) for 200GB of iCloud storage. Apple should be paying (according to the published pricing) between $2.50 and $5.50 per month to Amazon AWS for this. Add in a few pennies for Google’s storage, they are are probably break-even or slightly behind. If they were to operate their own S3-like storage, they would probably make a small -to- medium profit instead. I’ve calculated some numbers based on 2 MB per iPhone image.

per TB per month
2 PB – 1 billion
20 PB – 10
billion photos
200 PB – 100
billion photos
2000 PB – 1
trillion photos
-$5 -$10,000 -$100,000 -$1,000,000 -$10,000,000
-$10 -$20,000 -$200,000 -$2,000,000 -$20,000,000
$10 $20,000 $200,000 $2,000,000 $20,000,000
$20 $40,000 $400,000 $4,000,000 $40,000,000

Given Apple’s huge profits of nearly $70 billion per year, paying Amazon about a quarter a billion for worry-free, infinitely scalable storage seems worth it.

I haven’t included the cost of accessing the data from S3, which can be quite prohibitive, but I suspect that Apple uses a content delivery network (CDN) for delivering the photos to your photo stream.


Multi-cloud is clearly not a mythical beast. It is here and big companies like Apple are already taking advantage of it.


2 thoughts on “Apple’s iCloud is a multi-cloud beast

  1. jlkinsel

    Love Little Snitch. 🙂

    Not sure if your screenshots showing the data transfer are at the same time, but also note it looks like the transfer to google happened only at the beginning of the transfer (16hours “ago”) while s3 was ongoing. I wonder if it’s either they’ve found something Google’s better at (image API, faster network for clustering) or if maybe they’re doing it for legal reasons – separating the metadata from the data.

    Would be interesting to see how things look when you fire up iPhoto and it syncs photos down from iCloud…

    Morgan Stanley estimates Apple’s AWS bill is around $1B/year. There’s probably some compute in there as well. I can’t imagine Apple isn’t using S3’s replication feature, although that’d double storage cost and add in data transfer fees…

    1. Chiradeep Vittal Post author

      @jkinsel. The traffic to Google is way less (50 MB vs 1.3 GB). I suspect they are storing low-res images there for when the network access to S3 is down? From a conversation with @ianrae on twitter, it appears that they use Azure’s blob store as well (perhaps it is a regional thing).
      When Photos syncs photos from iCloud that it doesn’t have, it appears to use S3 only


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