Only the modified bits are downloaded or uploaded and significantly reduces the volume of data that is transmitted.
Delta Sync is in a testing phase and works for uncompressed formats. It is particularly useful for files that have been changed only slightly.
The feature is licensed on the server side under AGPLv3 and the client side under GPLv2, and can therefore be freely used and further developed by the community.
Delta Sync supports the following file formats:
- Crypto Container (e.g. VeraCrypt)
- Disc images (.iso /.img)
- Audio (raw audio formats /.wav /.aiff)
- Images (.svg /.tiff /.bmp /.dng)
- Video (raw video formats, e.g. uncompressed.avi)
- Virtual Machine Images (.vdi /.ova /.img /RAW)
- Microsoft PST Files (emails, calendar entries, etc.)
- Text Files
- Tar Archives
After the release, a testing phase will then begin, in which the community will be able to try out the feature and provide feedback.
This will be followed by stabilisation of the new sync algorithm and further testing, performance measurements and performance optimisation, until the feature is finally available to all ownCloud users.