Solid State Drives: is my data safe?

One of the most talked about issues with flash memory is that there are a limited number of program-erase cycles. Every article seems to mention this, and it seems quite scary.

Taken in context, though, this is not as a big a problem as it might seem. A single-level cell (SLC) flash memory may have a lifetime of about 100,000 cycles. To put this in perspective, if you were to completely fill your 256GB SSD with data 10 times a day, it would take you more than 25 years to reach the cycle limits. A hard disk would probably not survive that long either.

This ignores factors such as write amplification and garbage collection (that add extra cycles and potentially reduce the lifetime) and over-provisioning (that provides spare blocks to increases the lifetime of the flash memory). However, as consumer grade hard disk drives have an average life of 4 or 5 years so it doesn’t seem that there is any greater risk from using SSDs rather than HDD. Just make sure you have regular backups, either way. (And don’t store the latest backup in the same bag as your laptop. That will be really frustrating when the bag is stolen.)

The Tech Report website did an interesting experiment to test the lifetimes of a number of SSDs under conditions of stress. This is the last article in the series, but has a link to the first if you want to follow the whole thing: The SSD Endurance Experiment: They’re all dead.

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