Running external Hard Drive 24/7, reliable?

Question

So I have a router with USB storage features, I also have a Raspberry Pi 2 and WD external HDD 1TB.

I want to turn it into a NAS and torrent box, but I'm wondering if leaving external HDD plugged in all the time is safe? By safe I mean the HDD will not break after let's say a year due to constant read/write.

Answer 1

Probably the least helpful answer is that it will run fine until it goes wrong. A properly designed external disk will not run too hot, so the drive will run until it suffers a failure due to something wearing out. The life of the disk will on average not be changed because it's in an external box not inside a computer chassis provided you allow airflow and don't drop it. Actually, the life of a disk in an external box sitting on a shelf is probably a lot easier than the life of a disk in a laptop that is carried around and may be moved while running. I've run external disks for years (as in ... more than 5) with no problems and no bad sectors, I've had disks in servers fail within months. You could guess that there is a 2% chance the disk will fail within a year due to manufacturing issues and then it'll run for years before it reaches another 2% chance of failure. The write operations or read operations won't significantly change the disk life... I work with big NAS storage systems that run their disks continuously and are constantly writing / reading data and get maybe 1% a year of disks over 5 years old failing. So 5+ years of being busy isn't enough to wear out a (5+ year old design) disk drive. But like the financial guys say, past performance is no guarantee of future performance. It may be that new disks will prove more (or less) reliable... and you're running 1 disk not a stack of them, so a statistical chance of 1% failing in a year is not very hepful... your disk will either work faultlessly for years or will stop working suddenly for some hardware failure. But probably it will be fine for years.