The default file size for OneDrive (Formerly SkyDrive) has been 2GB for quite some time. While this was not an issue for the majority of files users worked with it was an issue for users uploading video or Outlook archive files. Today this limit has been increased to 10 GB which is large enough to back up almost all users Archive files. (Where we most often ran into the 2 GB limit)

Source: OneDrive Blog