Bit Rot: How Hard Drives and SSDs Die Over Time

A disintegrating hard drive.Daniel Krason /

Computer storage is both a blessing and a curse. We can store terabytes of photos, documents and more at home. But these data are more precarious than we might suppose thanks to a phenomenon known as bit decay or data degradation.

Hard drives and SSDs don’t last forever

Take a hard drive and a SSD and bury them with a book in a time capsule for 100 years. You can bet the book will be readable when it resurfaces, but storage results? Good luck.

It is not only because standard storage disks can experience hardware failures. Whether we’re talking about SSDs or old-fashioned mechanical hard drives, these drives have a limited capacity to keep data when they’re not working. No, doesn’t that mean you have to start keeping your computer on at night for fear of losing your photos, but that you are hiding a player full of personal movies in the closet for decades? Not the best idea.

We can’t start chiselling the 1s and 0s on the stone, of course. Also, if everyone suddenly printed all of their files on paper, we would quickly run out of trees. So what should we do knowing that our storage drives and the data they contain have a limited lifespan? You should basically be doing what you are doing now, or what you should have been doing all this time.

How readers store data (and how they can degrade)

A 2.5 inch black Samsung SSD on a white backgroundSamsung

Hard drives use magnetism to store bits of data (all those and zeros) in clusters. These bits can, over time, toggle, which can lead to data corruption if enough rollovers occur. To counter this, hard drives have an error correction code (ECC) which searches for bits that went wrong. If they are found, the hard drive will correct them, if possible.

SSDs have no moving parts like hard drives. They use a different method to store the bits. These readers use an insulating layer to trap the charged electrons inside the microscopic transistors to differentiate between 1 and 0.

There’s a lot more to it than that, but it gives a basic idea of ​​how the two types of storage store their data. Now let’s see how they can lose it by bit rotting. With hard drives, as mentioned above, the recorded bits can reverse their magnetic polarity. If enough of them return without being corrected, this can lead to decay of the bit. SSDs, on the other hand, lose their data when the insulating layer degrades and the charged electrons escape.

The time it takes to see bit rot in practice depends on a variety of issues. Hard drives have the potential to last with their data intact for decades, even if they are powered off. SSDs, for their part, would lose their data in a few years in the same state. In fact, according to some reports, if stored in an unusually warm place, data from an SSD can be erased even faster.

Under tension, these discs are another story. They usually last until they experience typical problems, such as hardware failures, or when SSDs are maximizing their read / write cycles. They can also lose data from common suspects, such as malware, firmware corruption, contact with water, or any number of random issues that have nothing to do with bit rotting.

How to protect your data from bit rot

Netgear ReadyNAS RN422 network driveNETGEAR

So what does a careful computer user do to avoid the risk of bit rot and other storage failures? The answer is pretty much what responsible computer owners are doing now.

First, pay attention to the health of the discs you are actively using. One way to do this is to check the CLEVER. (Self-monitoring analysis and reporting technology) status.

You can also set a retention period limit for an active hard drive or SSD. SSDs were previously not considered as reliable as hard drives when in use, but it is not as widely accepted as before. Most people can expect an SSD to last as long as the average hard drive.

A good rule of thumb is not to keep a storage disc for more than about five years. It’s just a rough estimate, and some people keep their discs much longer than that, waiting to fail. If you do this, however, it is extremely important that you have a reliable backup strategy.

Let’s talk about archiving discs first. If you’re storing data on a regular hard drive or SSD in a closet or safe, it’s a good idea to turn it on and let it run regularly. This keeps them in good condition and reduces the risk of bitten rot or other problems.

For a hard drive, you can probably get away with powering it at least once a year or once every two years to prevent the mechanical parts of the drive from seizing up. You must also “update” the data by copying it or use a third-party tool such as DiskFresh. SSDs are a bit simpler as they just need to maintain their charge; you can feed them for a few minutes about twice a year.

Another option is to look specially designed archive storage media such as Verbatim M Disc Blu-ray Discs which would supposedly hold their data for 1000 years. (Of course, you probably won’t be there to test this claim.) They are available in different capacities of 25 GB, 50 GB, and 100 GB per disc. However, their write speeds are slow for turtles, so be prepared for a long archiving process.

Whichever archiving option you choose, keep multiple copies of the archiving data in different locations to make sure you don’t lose your files.

RELATED: How to archive your data (practically) forever

Back up your files

An external hard drive connected to a laptop via USB cable.Anton Starikov /

Backups are something that few people like to think about, but they are easier than ever to make. In general, the best backup strategy represents three copies of your data. The first is the one you use daily on your PC.

The second is a local copy that you keep on a backup drive, which can be an external hard drive or a NAS enclosure. Windows 10 has a built-in feature called File history which will automatically back up your PC for you. Many other third-party tools for creating backups are also available. Alternatively, you can manually copy your personal files and folders on a daily or weekly basis.

You now have two copies of your data, but in the event of a house fire or flood, or if both drives fail at the same time, you will return to square one. That’s why an “off-site” backup is also a good idea.

The simplest solution is to use a cloud backup service, such as Backblaze. If privacy is an issue, many of these options allow you to encrypt your backups to prevent the service provider from seeing your data. For example, Backblaze allows you to create your own encryption password. However, if you lose this second password, you lose access to your backups.

Three copies of your data in different places should be enough to prevent data loss, whether your discs end up suffering from bit rot or some other calamity.

RELATED: What is the best way to back up my computer?

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