>>1455234>is there a threshold on data copying where it becomes harmful for your hardware?Yes, it's 1. Any use of your hardware damages it. It also decays over time if you don't use it.
Do it all in one go. Heat kills hard drives but you're not going to turn on cool drive, wait for system to detect it, write 100 MB, turn it off, let it cool down, repeat 39 999 more times to write 4 TB of data. The power cycling itself could be more damaging not to mention that if it takes 10 minutes including cool down and 8 hours sleep a day it would take you 1 year 1 month 21 days and 16 hours.
The difference in total heat energy input between turn on cool hd write 500 GB, turn off let it cool down, repeat 7 more times, and turn on once, write 4 TB, turn off is trivial.
There is no advantage I can see to splitting the copying over days unless you have to wait days for new data to be created. HDD data should last for decades between writes before bit rot sets in but best practice says you should also power them up at least one a year to prevent mechanical seizing, though I've never had any trouble with this.
