SSD Endurance

Carsten Mattner carstenmattner at
Thu Mar 12 14:17:22 PDT 2015

On Thu, Mar 12, 2015 at 10:10 PM, Matthew Dillon <dillon at> wrote:
> Not necessarily.  Data degradation is a natural process so it depends what
> the controller decides to do with it.  It will probably reallocate the block
> and bump the Reallocated_Event_Count counter in the smart status, but that
> doesn't mean that the SSD is going bad.  If the counter starts increasing
> regularly though that could be an indication of future problems brewing.
> The biggest indicator of problems is the Offline_Uncorrectable counter...
> that means data went bad that the SSD controller couldn't recover.  Flash
> wear characteristics are such that controllers are supposed to be able to
> detect and rewrite weak data before it actually goes bad so if data does
> actually go bad it's probably a good idea to replace the SSD.

Sounds like an SSD will take better care of write-once data compared
to a spinning disk.

> On Thu, Mar 12, 2015 at 2:00 PM, Carsten Mattner <carstenmattner at>
> wrote:
>> On Thu, Mar 12, 2015 at 9:42 PM, Matthew Dillon
>> <dillon at> wrote:
>> >     When left powered, SSDs do internal scans and will slowly fix up
>> > cells
>> >     before the data becomes unrecoverable.
>> Does that mean those cells are marked dead?

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