I read someone who noted a huge spike in their broadband usage after installation of iOS 5 and iCloud who couldn't work out where the data had gone.

My situation is that yesterday I installed iOS 5 to 4 iOS devices but didn't download any of the ipsw files (I already had them on a USB drive and each time pointed iTunes to the locally saved files so it didn't have to download the ~3Gb worth of update files.

One iOS device appeared to commence an iCloud backup including 2-3Gb worth of photos but minutes later I realised what was happening and stopped it and deleted the backup. Within the few minutes I suspect that I wouldn't have been able to upload much of the backup over ADSL.

The devices were subsequently set up to backup information only to iCloud (eg. contacts, reminders, mail) but NOT actual device backups, which are set up to sync to a local machine over WiFi.

This morning my internet stats show a huge spike to 1.3Gb download and 157Mb upload.

As a comparison, this month the highest recorded daily usage is 643Mb down and 48Mb up.

Any ideas what's going on here?

The original anecdote I posted above is of a person on my twitter who said:

“This whole iCloud thing's gonna be murder on NZ data caps. Apparently we've used 29GB *today*. Done v little other than updates/iCloud sync”