Initial sync with data already present on both sides

[tenox (Antoni Sawicki)]

Hi,

First of all thank you for making such fantastic product open source!

Recently came to face following scenario. I have two remote computers, which already have data synchronized by external means (example BTsync or HDD shipped by FedEx). It’s an untouched archive 100% identical on both end. Has about 100.000 files.

I have added it as a folder to sync on machine A then when shared with machine B selected the folder with existing data.

It looks like Syncthing started synchronizing files before it finished scanning. In the process it has deleted about half of the files and it’s synchronizing them over internet, which I don’t want because they were already there.

I also tried the same with adding folder on machine A, waiting for scan to finish and then sharing / adding folder on machine B. Same thing happen.

The question is, what is the correct procedure for establishing a sync on data that is already “pre-synchronized”?

Thank you

[Arneko]

Hello and welcome to the forum,

If the files were 100% in sync before you set up syncthing, then it may look like syncthing is transferring files while it actually is not. In an initial sync it sure as hell shouldn’t delete any files, because that wouldn’t make sense. Are you sure this is happening, i e can you actually see it in the folders or is that just the way you interpret the gui?

If the folders were not in sync but share mostly the same data with one folder being more recent, read this thread from 4 days ago

Re-adding a node that's been out-of-sync for months

Have a cluster of 3 devices which are in sync. Everything ok experiencing lots of updates/deletions/additions on every device. Have a fourth device who has been out-of-sync for months, has experienced deletions and additions on it’s side. This device has never been introduced to syncthing (it previously was on btsync, then didn’t upgrade like the others to syncthing). I would like to re-add this device but I want to be very careful with the risks of spontaneous deletions or additions this new …

[tenox (Antoni Sawicki)]

Yes that’s correct. I counted files and folders in the directory. The number dropped to about half and then Syncthing started transferring them over Internet slowly.

I can probably easily reproduce.

[tenox (Antoni Sawicki)]

I’ve got it resolved in this post:

what is the procedure of enabling sync of folders that are already "in sync" outside of syncthing

I have a hard disk with data. I made a clone of it and shipped to another location via FedEx. What are the steps required for me to enable ongoing syncing, without copying existing pre-synchronized data over network? Do I add it as a folder on one machine, wait for scan to complete, share with another machine and select the right disk on the other? Thanks!

the trick is to add both sides with same folder-id but do not share until initial scan is complete.

Thanks all for help!