What is Data Rot and how to prevent it?

19.11.2019 54

Data rot, also known as data degradation, is data decay that corrupts information making it unusable. That happens over time. No matter what kind of digital storage you have, data rot will occur, it is inevitable.

Data rot and Hard Drives (HDD)

HDDs are prone to many problems. They have moving parts and that could be a problem. Many of them eventually get their head broken. Their head can stop moving or scratch the magnetic disk. As for the magnetic disk itself, if you leave it for years without electricity, it will lose the data.

Another problem that you could have is corrosion, because the HDDs are made of metal.

Dust can also be problematic. If dust enters the drive, this could easily be the end of it.

There is no clear study that says exactly how long your HDD will last, but we recommend that you change it after 3-4 years. HDDs could last a little longer, but you will be putting your data at risk.

Data rot and SSD

SSDs don’t have moving parts, so that’s one advantage. Here the main problem is the electric leakage. The leakage happens when a NAND cell charge is emitted into the surroundings. The problem increases with the number of cell states. SLC – 2, MLC – 4, TLC – 8. To lower the number of errors, the SSDs have error correcting codes (ECC). As time passes, they will inevitably come across an unrecoverable error.

Another measurement for SSDs is the terabytes written (TBW). If an SSD is rated for 300 TBW, this value is the total capacity of written data over the lifespan of the drive. After that number is reached you can expect a fatal error.

Typically, an SSD can last for around 5 years without problems. It is a good practice to replace your SSD right after the warranty ends.

CDs and DVDs

CDs and DVDs are not safe too. There are many people who think digitalizing their old tapes is a great idea. No! They will show a critical error after some years. They are damaged by oxidation, physical scratches, dust, UV light and the adhesive they have. The sad part is that there is nothing you can do about it. If you prefer optical drives, create new copies any now or then.

If you’re a collector of rare disks and want to preserve them, keep them in a cool, dark and dry environment. If possible – in vacuum, but we know this could be too much.

Some manufacturers use Accelerated Life Testing to predict the lifespan of their optical drives, but these test don’t for account all possible factors, so take these numbers with a pinch of salt.

  • CD-R, CD-RW (unrecorded) 5-10 years
  • CD-R (recorded) 50-200 years
  • CD-RW (recorded) 20-100 years
  • DVD-R (recorded) 30-100 years
  • DVD-RW (recorded) up to 30 years
  • BD-R (recorded) 30-200 years
  • BD-RE (recorded) 30-200 years

Data from https://www.cdrom2go.com/media-longevity

A Solution for Data Rot

You just record all your data on blocks of stone. No, not even that will save you. Your best bet is the cloud. The storage of the cloud providers can also suffer from data rot, but they use the so-called RAID. It is a combination of storages that serves as backup. It indicates when to change an HDD with a new one, and automatically recovers the data of the broken one. The cloud is your best choice for preserving your important data for longer periods.