After a few tragic ends to some photos (poof, gone), I'm trying to get a good offsite backup plan in place. I was curious, and haven't been able to find a definitive answer in any of my resources: If I copy data to a standard SATA hard drive, and then unplug the hard drive and store it, how long will that data remain intact? How bout on a flash drive?
Hard drives, unlike RAM, don't need electricity to keep data once it's been written. Because of this, a standard SATA drive can store and maintain your files for extremely long periods of time, even if it's shelved in a closet away from a computer. The actual storage lifespan will vary, though.
The standard hard drive warranty runs about 5 years. That number is assuming regular use, so if a drive were to be plugged in and have data written to it infrequently, and stored in a dry space with optimal temperatures, there's no reason that it couldn't last far longer than that—in the range of seven or even eight years. Always keep the drive safe from large magnetic fields, since they could help to degrade the data much more quickly, and keep that temperature rule in mind, since there are movable parts with grease that could dry up and crack in the wrong conditions. The actual temperature range varies from drive to drive, but keeping it somewhere between 50 and 110 degrees is a pretty safe bet.
Solid State, or "Flash" drives, though still new, would theoretically last longer. That being said, you should never count on more than a solid eight or nine years, because the whole point of data storage like this is to keep it safe, not to take chances. Technically, it's possible for a NAND flash drive to last far longer than a decade in storage, but every unit is made differently, and some might have cheaper components than others. As for heat and magnets, an SSD will fare much better than a traditional hard drive (it would take a supermagnet to even begin to affect one).
The basic thing to remember here is to check the data on the stored drives once every few months, just to be sure that it's still intact, and to invest in a replacement for the drive every few years. Other than that, all you can do is keep them safe, and hope for the best. Photo by Carl Berkeley.
If you're looking for a more daily-use sort of storage option, see our best solutions for massive amounts of storage. If you're curious about how to make your solid state drive last longer, check out our guide for maximizing the life of your SSD.