FreeFileSync Open Source File Synchronization

Performance Improvements

FreeFileSync can perform multiple file accesses simultaneously. This speeds up synchronization times dramatically in cases where single I/O operations have significant latency (e.g. long response times on a slow network connection) or they cannot use the full bandwidth available (e.g. an FTP server enforcing a speed limit for each connection).

You can configure the number of parallel file operations per device in the Comparison Settings dialog. It is evaluated for all folder pairs of a configuration as follows:

• During comparison FreeFileSync groups all folders by their root devices.
  For example, consider a configuration with two folder pairs and parallel file operations set up:

  C:\Source	↔	D:\Target
  C:\Source2	↔	E:\Target

  Device root	Parallel operations
  C:\	1
  D:\	2
  E:\	3

  FreeFileSync will put the folders C:\Source and C:\Source2 into the same group for device root C:\ and allow only 1 file operation at a time. Folder D:\Target will be traversed using 2 operations, and E:\Target using 3 operations at a time. Overall, FreeFileSync will scan all four folders using 6 parallel operations.
  
  
• When synchronizing a folder pair, FreeFileSync will use the maximum of the number of parallel operations supported by the two folders.
  
  In the previous example the folder pair C:\Source ↔ D:\Target will be synchronized using 2 parallel operations, and C:\Source2 ↔ E:\target will be using 3.