Ok, so I have searched this for a while, and I can't find a correct answer people also give different ones. So I'm going to you guys, becuase I trust you haha.
Here it is, I have a few external hard drives. I know I should unplug them from the pc via safley remove hardware, but what about turning them off? One of mine has a power button, and the other two do not.
1) They suck up "some" power, so it seems like a waste. I turn off my PC every night, so why not turn off my external hard drives.
2) They are loud when I'm trying to sleep.
3) They could live longer?
Is it even safe to just, unplug them? Not while they are connected to the computer obviously, just if they are plugged in doing nothing, they are still running. I read on a few sites that you are supposed to leave them plugged in, but that seems idioc. I just need a straight answer.
If you turn off an external drive while it has dirty buffers (write operations that have not yet been sent to the disk, or not yet finished by the disk), in the worst case you will loose like 40% of your filesystem, because of corrupted/inconsistent metadata. You should always disconnect external harddrives using the Safe Hardware Removal procedure; right click the icon in your system tray and let the system write any last changes, before you remove power from the drive.
Also be aware of APM/spin-down options harddrives may have, which reduce noise. And yes you can unplug them, but only after you safely removed the device from your operating system.
Sorry i read your message a bit too fast indeed. Yes, after you safely removed the device, if it does not power down by itself you can flip the power switch of your external HDD cases. After the "safe removal" procedure is complete, there will be no more data transmissions with the drive; so there can be no powerdown while writing something.
After following the "Safely Remove ..." procedure it is safe to turn off (or unplug) the power for the external drive(s). But you do NOT need to physically disconnect from the computer. With no power to the drive, it is electrically "dead" and the computer will see that there is no device connected on that port until its power is restored.
And yes, you should do this to prolong the life of the external drive. It also eliminates possible damage to the drive from power glitches, or corruption from odd software or even malware. If you are really worried about power surges, complete disconnection, both from the computer's data port and from the drive's power supply, is the super-cautious step.