Question Long term photo backup - How long can a HDD hold data without power?

Feb 27, 2020
I'm looking to backup TB's of photos which are totally irreplaceable. I have two offsite cloud based backups with Backblaze and Flickr and I'm looking to add another backup that is a bit more physical. If I was to copy nearly 3TB of data onto a 4TB HDD and then put it into a safe deposit box, how long would the data "survive" for? I won't need to add any more data to the drive as these were many thousands of photos that were scanned in over 3-4 years and have since sadly been destroyed in a fire. I did look at triple layer Blu-Rays but at £200 per 500GB it will work out very expensive. I also imagine that a scratch on a Blu-Ray disc could wipe out a noticeable chunk of data!

Some sites say data can survive for 8 years and some say over a decade. Then of course you find articles about the defunct Megaupload site where the hard drives were unreadable after only 4 years. Also, what would reset the timer? If the data would survive for say 6 years and I pulled the drive out at 5 years and powered it on for 5 minutes, would that give it another 6 years? Would I have to defrag it or something, run a disk check maybe?


Nov 1, 2019
Another good option is storing them on dvds such as archive discs or sd cards, as long as a sd card isn’t being used much it will last basicly forever I have sd cards from when they first came out and they still work 100% even though they are like 4mb lol


My thoughts:

First: do some reading to understand how a HDD actually works and stores data.

For example:

You can easily find other similar links with more explanations and details.

Second: there are numerous factors involved. Just the basic quality of such devices has declined - they are not made as strong and as durable before. You can see that in almost any products nowadays. Even SSD's seem flimsier....

Many products now have a built in EOL (End of Life). May simply degrade with time - plastic components, metals that corrode albeit slowly.

Safe deposit boxes may be okay. However, premise is that the bank will always be there - no way to know that. Plus if you the sole owner, your death or some incapacity may make it difficult for your heirs to retrieve the photos or anything else stored therein. Have multiple owners: not just the bank accounts but the box as well.

You should not need to regular power checks, health checks, and certainly not defrags (which are for HDD's only). However if doings such tests and maintenance provides you with a high level of assurance then do so.

Just remember that anything you do could cause data loss just as a statistical matter. Be it plugging in the drive to test or dropping the drive in the bank vault...

The main safeguard is duplication. Data saved and stored using different media and locations.
My guess is that data will be retained for a very long time.
But, I suggest you pose this question to the various HDD makers such as WD, seagate, hitachi.
They can give you an authoritative answer.
They might also be able to identify their own products that might have the longest life.

Whatever the lifetime might be, make at least two copies and store them in two different vaults.
On some sort of a schedule, copy them and compare them.


Mar 10, 2017
I read somewhere that HDDs that are used in surveillance are amongst the best of the best - I never tried them, I don't know.

Make sure the copy process actually succeeded by checking several throughout the spread just before you safe-deposit-box them. I too recommend two sets, each set a duplicate of the other.

What copy program will you be using? I recommend TeraCopy or anything similar that will give you a real-time report of what was copied and what was not copied. Also, copy in "clumps", in groups that make sense to you.