The feature you are asking is called "Block-Level File Copying".
With this feature, when you make a change to a file, rather than copying the
entire file from your hard drive to the cloud server again, only the parts
of the file that changed (called the delta) get sent.
A Google Drive sync cannot be partial.
If a small change is made to a large file, it redoes the entire file rather than just the change. Google Drive isn’t capable of doing block-level file copies.
As far as I know, among the best-known cloud providers,
only Dropbox has this feature for all file types.
Dropbox partitions every single file it stores into 4MB blocks. Each block is hashed with SHA-256 and a list of these hashes gets stored in what’s called a “blocklist” for reference.
This feature is also shared by OneDrive, which however only supports it for
Microsoft Office documents.
For more information and some benchmarks, see the article
Block-Level File Copying and the Cloud.
pcloud offers block level sync too: https://www.pcloud.com/help/drive-help-center/does-pcloud-support-block-level-sync
– Haydentech – 2019-07-22T16:22:02.610Since
blocklist
is considered for "Block-Level File Copying"; when a file is updated (a character is added at the beginning of the file), does Dropbox re-upload the complete file since the first block's hash will be change and it will also affect/change the hash of all the consequent blocks. @harrymc – alper – 2019-09-29T16:20:43.727@alper: I suppose it will. – harrymc – 2019-09-29T16:37:58.907
As I understand since there is a case that whole file can be uploaded using "Block-Level File Copying", it creates duplication, could there be better approach to handle this, such as Git patches? @harrymc – alper – 2019-10-02T14:09:04.130