HOW LONG DOES AN SSD LAST?

The first is the price and there is little to debate here. Although SSDs have been falling in price until the end of 2016 (they have risen in 2017), hard drives are - today - unbeatable in cost per GB. Regarding the second factor, in terms of resistance and reliability, there are more doubts that we are going to try to clarify to find out how long an SSD really lasts, a question about resistance and longevity that many users ask when making the leap to solid storage. We always talk about the consumer market because at the moment in servers and data centers that demand maximum reliability in 24/7 tasks, the use of hard drives is still massive.

Let's remember to begin with that SSDs use NAND flash memories to store information. The wear and tear of memory cells is inherent in this technology and successive writes erode individual memory cells in both capacity and performance. For this reason, SSDs include additional free memory cells so that when the others fail, they do not lose capacity and also automatically reallocate the bad sectors to avoid losing data or performance.

The improvement in robustness and endurance in recent generations of solid state drives has brought their mean time between failures (normalized as MTBF) closer to what a typical consumer hard drive offers. Endurance tests aimed at "crushing" SSDs have shown that current models last longer than promised in the official specs and endure an enormous amount of writes that a standard user will not achieve before replacing them with one of greater capacity or performance.

But how long does an SSD last?

Manufacturers tend to evaluate the reliability of their drives by three factors: standard age (like any warranty), the total Tbytes written over time, and the amount of data written to the drive per specific amount of time, such as one day. . If we add the very diverse use of equipment and users to the three factors, together with the different types of memories used, we see that it is difficult to specify an exact time.

The warranty offered by the manufacturers already gives us a clue. Consumer models offer a three-year warranty, while premium models have a five-year warranty. Recently there have been several studies that try to determine with greater precision the useful life of an SSD. Some of the best known in addition to the Tech Report referral are:

Google and the University of Toronto. A study that evaluated the failure of SSDs in data centers and concluded that the age of the drives was more decisive than the write values   themselves. SSDs lasted longer than hard drives, but had more errors during their lifespan.

Facebook the Company examined the lifespan of the drives it uses in its corporate data centers, finding that they lasted significantly longer than the manufacturer's allotted. Of course, compared to the Google study, it found that the amount of data written was the key to determine its useful life and the beginning of failures.

Conclusions

A typical user does not have to worry about the strength and longevity of an SSD, because its useful life goes well beyond the warranty period of 3 to 5 years offered by the manufacturers and the amount of written data that they cite as a minimum and that they are quite conservative. It is likely that it is a normal scenario to replace the computer with the storage drive intact.

Nor has performance been affected in testing. Losses are observed as the unit ages but they are so light that in normal use they will be practically negligible for the user and in some SSDs they do not even exist, maintaining the advantage over hard drives. There are possibility of recovering data from it using data recovery software. 

Of course, it should be mentioned that most of the tests carried out so far have been carried out with MLC and SLC memories, which are now reserved for professional models, because manufacturers have bet on consumer models for NAND TLC flash memories (triple level per cell). A format that offers greater storage density and lower costs, but which can -in theory- lower the resistance compared to the previous ones.