Categorized | Online Backup Services

How synchronisation with online backup works

Increasingly online backup services have adopted synchronisation features as standard in their various backup plans. In this article I will closely examine how synchronisation works, and discuss the benefits and the pitfalls.

Synchronisation is the process of allowing two or more computers to mirror the data stored within their storage devices. It can take place between a workstation and server, between multiple workstations or a combination of both. However where combinations are used in most cases the server will act as a node which be the "bridge" between the various workstations. So no horizontal synchronisation actually takes place. As demonstrated in the diagram below

How synchronisation works with online backup

A software utility is provided by the online backup service which runs in the background at all times monitoring changes made to files. It is the job of the utility to monitor for file access and modification. A user may be working on two computers at the same time so the software needs to work out which version is current and to prevent users from editing the same file simultaneously which may lead to data redundancy.

Often it will upload a file automatically to the server when changes are made to a file and then unlock the file for access by another computer or user. The other computer will then receive files from the server in cases where the file saved on the server is more recent.

This isn’t always as straight forward.

Challenges posed with synchronisation

In most circumstances synchronisation works seamlessly, however there may be some instances where it does not go smoothly, some examples are listed below.

  • When a file name somefile.doc is left open on Computer A without saving changes, and then the user reopens file in Computer B and edits and saves changes which is then uploaded to the server. User then returns to Computer A and finds somefile.doc open and may save the file causing the user to lose all changes made from Computer B. A solution to this problem is to use file locking, this is used very well by SugarSync, it will alert the user that a newer version of the file is available on the server, and will ask you to either a) make another copy of the file or b) ask you to close the file without saving to download the newer file.
  • Drastic changes made to directory structure of synchronised folders may cause data redundancy, in the case of moving a folder, the utility may misunderstand this to mean that a user has deleted a folder. This may cause files to be deleted as well. It’s always best to manage any movement of folders from the online backup utility first.
  • Cross user synchronisation is always a challenge, many online backup services will deal with this problem by creating multiple versions of a file, in the case where two or more users have edited a file at the same time.

Benefits of Synchronisation

In a world where users own and use multiple devices, and increasingly smarter mobile devices which can open and edit files designed for desktop computers. There is a demand for synchronisation features which take the hassle out of file management across computers.

Although synchronisation isn’t perfect it’s still provides some very useful benefits, which can save time and potential data loss caused my user error by overwriting a more recent file with an older version.

It allows users to worry less about where they may have saved a file, and spend less time searching for them. All the folder structures and files are kept consistent across all computers, so users can focus on their work or art rather. Because the files and folders are kept exactly the same across all computers, the folder structure is familiar and much easy to navigate.

A great service that has fantastic synchronisation features is SugarSync and you can read the full review here

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