Understanding Synchronization

Synchronization works in two phases: analysis and synchronization.

Analysis Phase

In the analysis phase the program compares the contents of the folders to be synchronized to determine where there are mismatches in their contents and how to copy files so that the most current version of all files are propagated to all folders. The results of this analysis is provided to the user as a set of messages grouped in collections. You can review and revise actions planned, if necessary (e.g., you may want the older version of a document propagated instead of the new one). None of your files is changed during the analysis phase.

Synchronization Phase

In the synchronization phase the plan prepared (and possibly modified by you) during the analysis phase is carried out. Files are copied as necessary to synchronize the folders that are part of the synchronization job.

If the synchronize phase is started without first doing an analysis phase, both phases are executed, but you don't have a chance to review and modify the plan. Be sure to launch the analysis phase before synchronization if you are not sure about possible file version conflicts.

At the end of the synchronization phase, the program stores service information about synchronized files in a special folder, \_sync.app (one for each synchronized folder). This information is used to reliably monitor file changes for the next synchronization run. It also allows file deletions to be handled correctly. If you configure the program to propagate file deletions, it is important to review the Deleted files message collection before launching the synchronization phase.

Synchronization Algorithms

Some of the key characteristics of the Allway Sync synchronization algorithms are:

• Implements true all-way (two-way, three-way, etc.) synchronization.
• Uses only standard file system services. Does not require system injection, hooks, drivers or any other means that can make your system harder to manage.
• File and folder metadata for each synchronization session is collected and stored in a database.
• The most recent file version is determined based on a combination of file attributes, size and time-stamp (not just the file modification time).
• To ensure the safety of your data, when there is uncertainty as to which file is the most recent, the user is prompted for confirmation.
• Multiple instances of Allway Sync with access to a common file system can share common metadata databases.
• In the event of network, hardware, or software failures during synchronization, none of your data is damaged.
• Optimized to meet a high standard of performance.
• Stores information about deleted files and folders in the metadata database.
• Does not rely on the accuracy of the file system or computer clock.
• Creates and maintains the proper folder structure when needed to properly synchronize files and folders.
• Synchronize data other than simple files, including: registry keys, database records, messages, contacts, playlists, etc.

These algorithms were developed by a team of prominent mathematicians, and provides many unique benefits to the users of our software.