Effect of "Use symlinks during incremental backup"

Could somebody please explain what the effect of this option?
What is the difference whether this option is enabled or not?
If it is not enabled, will hardlinks be used instead of symlinks? Any effect on performance?

Sorry, just found it in the documentation.

But still one question open: what happens if I disable the setting after some backups have been made with the option enabled?
Will existing symlinks be replaced by hardlinks?

I wonder what will happen if I turn off on already created backups. Do you already know the answer? I have 3.5TB files with symlinks.

I didn t tried, but i am pretty sure it will only use hardlink for new files.
If urbackup was do do this , i think it would need to be in a maintenance mode like for rebuilddb/repairdb/remove unknown

Yes, it creates hardlinks. Have tried it. But did not notice any difference in backup performance.

With Simlinks enabled, when you move your urbackup_repo to another system you cannot read the data. You can see shortcuts and when u try to access the data you can error message - data not available in hdd.

When you disable simlinks, You can read the data after moving your urbackup_repo to another server (which does have any urbackup instance running).