A Quick Guide to Online File Storage Synchronization

For those people who have decided to store only one version of any file at given time, read no further: but don’t come crying if you lose your one and only copy! On the other hand, for those who want to copy, back up, share, or work on files from different locations and devices, here’s a short guide to online file synchronization – also known as syncing.

Syncing Starts With the First File Copy
The question of syncing arises as soon as you copy a file and change the original. Is it sufficient to copy the latest changes from one file to the other, and simply overwrite the destination file? Or is some more sophisticated system needed so that all changes, wherever they are made, can be safeguarded for later use? One-way syncing is a possible solution. In this case, any changes you make to the original (the master copy) are then reproduced in other known copies of the file. Online file storage solutions may offer the automatic mirroring of changes on a real time basis, or schedule backups at regular intervals. Whichever solution is used in one-way syncing however, no data is ever copied to the master copy, but only from the master copy.
Two-Way Syncing
Now let’s say you have a file that exists on two or more different computing devices; a desktop PC in your office, a tablet PC at home and a smartphone you carry around with you, for instance. Depending on where you are – in your office, at home or out traveling, you might want to make modifications to the file on any of the devices. But you might quickly end up with divergent versions of the file that you cannot simply copy from one device to another without loss of data.
Keeping Tabs on What Changes Where
Online file storage providers have a solution here too. In this case two-way file synchronization copies changes in both directions: the idea of a master file doesn’t apply here, because all known copies of the file will be updated whenever a change is made in any one of those files. To do this, the online file storage provider must keep a database of information about files to be synchronized and indicate potential synchronization conflicts to the user. Choices for resolving the conflict may then include overwriting files, merging their contents or saving one or other changed version to a new file.
Online File Syncing and Recovering Past Versions
More advanced syncing includes version control: instead of just overwriting all the files each time a change is made to one of them, the previous version of the overwritten file is also saved (and perhaps the version before that, and so on…) This means you can recover a previous version of a file if you make a major change to the current version, and then wish you hadn’t done so. Backing up previous file versions online can also be handy when the file (and maybe also a folder of files) is synced not just between different devices, but between different users too. That way, you also have a chance of recovering a shared masterpiece if somebody else’s editing turns out to be too heavy-handed.