How cloud backup applications like Carbonite can backup an small change in a big PST file?
For example: a 5GB pst file located in c:\pst has been already backed up in the cloud. If the user opens outlook and receives 10 emails, the pst files changes and the PST needs to be back it up again into the cloud.
But, after a couple of hours, the pst file in the cloud is in sync with the user pst file.
I notice this happens with Dropbox as well. I moved 1GB pst to the dropbox folder and waits for the file to be uploaded into the cloud. I open outlook and add, remove some emails. The pst file changed and a few minutes later, the file were in sync. The full pst file were not uploaded.
How cloud backup applications upload only the "changes" of the pst files? any idea?