Delta sync

From PowerFolder Wiki

PowerFolder analyzes the file which is supposed to be transferred. It compares the latest version with the previous version. Then it selects the changed parts and transfers only them. This feature is called delta sync and makes most sense if you have big files/folders and/or low bandwidth. PowerFolder needs to analyze each file, so this feature takes some extra resources (I/O and CPU), but reduces the transfer time.

It is possible to control the use of Delta sync for LAN and WAN connections under Preferences/Advanced.

Data integrity check / Checksum

PowerFolder calculates multiple checksums on files that get transferred with PowerFolder (with or without Delta Sync) to ensure the data integrity.

• One MD5 checksum is built over the entire file
• Each transferred file part is also checked with MD5
• In Delta sync also a so called rolling Adler checksum is built to calculate the changed files parts (deltas)

This checksum building ensures that a file is absolutely identically on the source and target computer after transmission.