Is it possible to connect the HDD with an existing file system to a USB3 port?
Is the NTFS write is working stable with OpenWRT?
I have a professional 8 port USB3 with 3A/12V external power.
Is the capacity of 8TB with GPT could be problematic when I want to use this disk with the NTFS filesystem?
I assume it's a 3.5" HDD?
Not sure if you can power that from a USB hub.
It's a 3.5 USB3 HDD.
Okay. Do you suggest I must to try?
Does it have its own power supply?
If yes, then it's OK, power wise.
NTFS works in openwrt, but it's not the best file system, when it comes to performance.
The performance it's not main purpose, the maximum speed HDD is about 150 MB / s in theory, but I think that will not be a problem
Is it safe to write on NTFS like a NAS, and write from OpenWRT like pyload or transmission?
Just as safe as in any other Linux based OS.
Most consumer NASes don't use NTFS.