File synchronization

File Synchronization (also file synchronization, file synchronization or short Filesyncing or file syncing) is the transfer of digital files (English Files) and automatic execution of all necessary file transactions to generate a unified data store in different places. In common parlance, file synchronization is primarily associated with internet-based file services for the cross-device comparison of file stocks, as has been popularized by Dropbox since 2010, for example . However, file synchronization can also take place within a computer network or between different folders on a computer (for example via rsync ).

functionality

File synchronization requires at least two devices involved, i.e. workstation computer , notebook , tablet computer or smart phone on which part or all of the data is to be synchronized. However, file synchronization is limited to a device-to-device relationship and the number of devices involved can be significantly greater.

The goal of a uniform database across all devices is achieved by file synchronization through continuous monitoring of the file system and the ongoing comparison of the files. When a file transaction is carried out, such as file creation, deletion and modification, this is identified and the necessary instructions and information are transmitted to all other devices involved. For example, if a file is created on one device, it is transferred to the other devices involved and saved there. If a file is changed and a version with a newer version is created, this is also transferred and the old version is deleted or archived.

Are central to the function of the file synchronization time stamp (English timestamps) files. Timestamps contain information about when a file was created, modified, or deleted. You are thus signaling the synchronization software what to do with a file. Example: If a file example.txt on device 1 has a change date that is before the date of the file on device 2, the synchronization software knows that changes have been made to the file on device 2 and must therefore be transferred to device 1 . Meta information from files to which time stamps belong is logically transferred when the files are synchronized and saved on the target device.

The synchronization can be initiated manually or automatically (for example by a specific event or at regular intervals).

Fields of application

File synchronization is particularly important for distributed and mobile teams. The synchronization - especially if triggered automatically - ensures that file changes are immediately made available to other team members.

Another popular application of file synchronization is the data synchronization between two devices of a user, for example between a computer at the company and a computer at the home office.

You can often see that synchronization software offers additional convenience functions in addition to the pure sync functionality. These functions include:

File sharing (then often called 'Sync and Share')
File versioning
Online editing of files
File comment

Technical implementation

The technical implementation can take place in different ways. A distinction must be made in particular between the architecture decisions made by the software developer and the sync algorithms used.

Most software solutions use a client-server architecture. Popular public cloud providers such as Dropbox and OneDrive use these as well as the popular private cloud solutions ownCloud and Seafile . Other solutions use peer-to-peer or hybrid approaches ( e.g. TeamDrive ).

The handling of file changes is also different. While some file syncing solutions support delta coding ( e.g. Seafile ), other solutions have to transfer the entire file when a change is made ( e.g. Nextcloud ).

File synchronization provider

The provider market for file synchronization is confusing. There are numerous companies that offer file synchronization as a service. The price models and the other scope of the offer can be very different.

There are also providers of software solutions with which work groups or, in particular, companies can set up and operate their own file synchronization infrastructure and thus make themselves independent of a service provider. Aside from the central synchronization function as core functionalities, the solutions differ in terms of extended functions as well as performance, adaptability and scalability.

Many NAS from manufacturers such as QNAP or Synology also have file synchronization functions.

Well-known providers of file synchronization as a service

Well-known providers of file synchronization software

Individual evidence

↑ What is file synchronization? In: support.office.com. Retrieved August 12, 2018 .
↑ LMU Sync + Share. In: uni-muenchen.de. Retrieved August 12, 2018 .
↑ QSync for file synchronization. In: qnap.com. Retrieved August 12, 2018 .
↑ Sync files between Synology NAS and the computer running Cloud Station. In: synology.com. Retrieved August 12, 2018 .

[1] What is file synchronization? In: support.office.com. Retrieved August 12, 2018 .

[2] LMU Sync + Share. In: uni-muenchen.de. Retrieved August 12, 2018 .

[3] QSync for file synchronization. In: qnap.com. Retrieved August 12, 2018 .

[4] Sync files between Synology NAS and the computer running Cloud Station. In: synology.com. Retrieved August 12, 2018 .