syncthing is retransmit all data in file or only block changed

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1

Dear All,

Need help , I want to use syncthing to sync big file. I want to know if i only changed some data in the middle of this file. The whole file will be transmit or only transmit block changed.

Thank you

2

Please check https://docs.syncthing.net/users/faq.html#is-synchronization-fast.

3

Thank you for your reply. in fact I review it before I post. It mentioned if append data, it will support transmit block changed. but My question: if data insert in the middle of file or delete some part what happened?

4

As far as my understanding goes, it does not matter where in the file you append the data. Syncthing should synchronise the modified blocks only.

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5

You can’t “insert data in the middle of the file”, no drive/filesystem supports inserting in the middle, there is no way to move the remainer for the file further to make a gap to insert data.

You can only overwrite the data in the middle, or you have to rewrite the remainer of the file to simulate an insert.

6

Thank you very much

7

Thank you, so what will happen

8

Different things can happen depending on details. Why don’t you try it and see if it works for your purpose or not?

9

I confused what I see. I use syncthing to backup mongodb. It keep doing scanning ,upload(when uploaded 80%, it reupload from scratch) then stoped(red color stop come out at web gui). I am very strange about this.

10

Syncing live databases will definately lead to corruption of a database don’t do that.

Databases usually use mmapped files which are not supposed to be synced.

11

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