I've been reading about backup solutions and have come across a number of people saying they use a USB external hard drive as part or all of their backup solution.
Are USB hard drives really sufficiently reliable to use for backups? From what I read in the past (e.g., Why I'm done with portable hard drives | Computerworld Blogs) they are rather failure-prone, especially apparently USB-only ones where the USB controller electronics have a high failure rate. Personally, I've only ever had one, a mid-price Western Digital, which has had some issues and I stopped using.
I understand there are some factors that substantially affect reliability, which AFAIK are whether the drive is moved much, whether it has its own power supply, and whether it has adequate cooling. Perhaps the drives are more reliable now than they used to be? Perhaps if they last through an break-in initial period they then tend to be reliable?
Best Answer
"...part or all of their backup solution."
USB HDDs for part of the solution is okay. For all of the solution, it's not a good idea.
When you plug in your USB HDD, your entire backup medium is now online and writable, on the same machine which has your primary data.
In the event of:
You could lose all your data, even your backups.
One poor-man's solution would be to use two HDDs, keeping one off-site and off line (e.g., at a friend's house).
The disks are reliable. Some USB electronics are flaky, so test your backups.