Percentage lifetime used on the SSD: 90%. Is that good or bad
smartssd
According to my SSD SMART information, "Percentage lifetime used: 90%."
Does it mean the SSD's remaining lifetime is estimated to be 10% or 90% of its entire lifetime?
Best Answer
It means your drive has 90% "life" left.
After some additional research, I came across this Crucial.com article that mentions the following:
In regards to the attribute named “Percentage Lifetime Used” (sometimes referred to as “Percent Lifetime Remaining”), this is simply a metric for how much wear life is left on your SSD. A solid state drive, like any flash memory-based storage device, has a limited amount of data which can be written to the memory blocks before they start to lose their reliability, and eventually go into read only mode. Your Crucial SSD will keep track of this life with SMART attribute 173, “Average Block Erase Count.” The Lifetime Used is a reflection of the block erase count in terms of a percentage. For example if your drive is rated for 3000 block erases and you have a total of 100, your Percentage Lifetime Used would be 100/3000, or 3-4%. For percent lifetime remaining we would simply take (3000-100)/3000 = 96-97%. These attributes are not a full picture of the health of a drive, but an expectation of how much usable life is left.
Because the attribute is vendor-defined, it can be complicated and confusing to figure out how each drive implements it.
Try running the Crucial Storage Executive tool to get a more accurate SMART reading that (should) follow Crucial's definitions by the book.
Here is a recent article on Google's experience with SSDs. It was based on:
Millions of drive days over 6 years
10 different drive models
3 different flash types: MLC, eMLC and SLC
Enterprise and consumer drives
Key conclusions
Ignore Uncorrectable Bit Error Rate (UBER) specs. A meaningless number.
Good news: Raw Bit Error Rate (RBER) increases slower than expected from wearout and is not correlated with UBER or other failures.
High-end SLC drives are no more reliable that MLC drives.
Bad news: SSDs fail at a lower rate than disks, but UBER rate is higher.
SSD age, not usage, affects reliability.
Bad blocks in new SSDs are common, and drives with a large number of bad blocks are much more likely to lose hundreds of other blocks, most likely due to die or chip failure.
30-80 percent of SSDs develop at least one bad block and 2-7 percent develop at least one bad chip in the first four years of deployment.
SSD UBER rates are higher than disk rates, which means that backing up SSDs is even more important than it is with disks. The SSD is less likely to fail during its normal life, but more likely to lose data.
Best Answer
It means your drive has 90% "life" left.
After some additional research, I came across this Crucial.com article that mentions the following:
Because the attribute is vendor-defined, it can be complicated and confusing to figure out how each drive implements it.
Try running the Crucial Storage Executive tool to get a more accurate SMART reading that (should) follow Crucial's definitions by the book.