The bigger it is, the harder it is to fall
Years ago, it was suggested that as HDDs and the RAID arrays they are part of grow in size, there will come a time when eliminating bad bits will be impossible. A huge number of bits in a petabyte array means that at least some drives likely have bad sectors that you are not aware of. As with painting an impossibly long bridge, by the time the self-scan is complete, the sector you started scanning will have a new problem.
This doesn’t stop the array from growing, but it certainly reduces the lifespan of the drives in the array. Backblaze has seen Secure Data Recovery report that his average MTBF is 2 years and 10 months. They questioned the accuracy of their findings because of the relatively small sample size and surprisingly short lifespan. SDR was generous because he died in
The tests included 72 different models, excluding failed boot drives, drives with no SMART data, and drives with data out of range. Let’s take a look at the models tested at Ars Technica and the number of failures.
