I am currently using rsync to backup the files of my main hard drive to an USB Drive connected on the same PC.
I would like to replace this rsync solution by Syncthing.
Is it possible to create on the same computer (without creating a Virtual Machine) 2 Syncthing instances so the same PC would be seen as 2 different Syncthing nodes?
Syncthing uses hashing and encryption, which cannot be disabled.
This means, that Syncthing will use CPU and RAM resources, even when using two instances on the same PC. So Syncthing is the wrong program for your scenario.
Note that rsync is also not backup, in that sense, so the comparison is valid. Paired with filesystem snapshots, or ignoreDelete or just versioning Syncthing is an OK tool for backup. I use it for that purpose.
But do consider the snapshots, versioning and so on.
Each instance will have to listen for connections on a different port. This might be automatically handled, but I am not sure.
I have had trouble getting local discovery working on a single node. The broadcasts don’t work so well. Configuring each “node” to connect directly to the right port should resolve this. Global discovery might work, but I’m am not sure.
The GUIs, if used, will be hosted on different ports. This may make it difficult to use wrappers (e.g. SyncTrayzor)