I am on a free hosting service which offers me cpanel.I want to have dropbox like syncing of my files on their server and my local hard disk, this way it serves as a backup and i do not have top upload everything i change. Is it possible to have real time "block level"(only changed chunks) sync exactly like dropbox?
I'm not aware of a real-time option that would be available with the access level of a normal cPanel user, but you could setup a regularly updated local copy using rsync if your host allows SSH access (some don't but many do) and has rsync installed (most do as many hosts use it as part of the backup routines).
Ensure that the
If you have databases in your cPanel account you will need to do some extra work as they are usually not contained in your home directory (and if they are, they can't be safely backed-up "hot" anyway). To get these you would need to set a cron-job on the server to backup the database(s) into your home directory regularly, ready for the rsync process to grab them. Don't compress such backups as this will make the rsync process much less efficient (or if you do compress them, use a compressor that has "rsync friendly" options). Be careful not to backup the databases too often - backing up a large database can be quite I/O intensive and a shared host will take a dim view of one using imposing an "unfair" amount of I/O load on a server.
This would be a one-way solution unfortunately.