Archiving on hard drives?
Now that disk drives are cheaper per gigabyte than tape cartridges, you might be tempted to archive data on disk drives and stick them on a shelf. Don't do it! Your data won't last.
The reason: the bits on the hard drive will gradually lose their magnetism, sometimes in as little as 12 months. Disks automatically rewrite marginal data blocks on the fly.
That doesn't happen when the disk is powered off.
The big guys do it Enterprise storage arrays do disk grooming in the background. They also look for bad blocks and other problems that are less painful to fix when the system is running normally.
Some arrays spin down or even power off disks to save power and cooling while extending drive life. These systems include logic to power up drives and check the data on a regular basis.
So leave that drive plugged in! If you want a couple of extra drives for archiving just buy some USB drives. They are cheap and work with any system. At idle they use about the same power as a nightlight.
The Storage Bits take Disk drives are used for archiving all the time. But they aren't just powered off and put on a shelf.
If you need that, buy a tape drive. Properly stored tapes will last for decades.
Comments welcome, of course.