solid-state drives

Jelle Hermsen jelle at
Fri Aug 3 07:52:46 PDT 2012

On 08/03/2012 02:04 PM, Pierre Abbat wrote:
> I don't see why you can't, or shouldn't, dedup an SSD. Deduping looks 
> for identical sectors and frees one of them; since an SSD is 
> completely random-access, there's no penalty for having some sectors 
> far from the file's inode. Recopying an SSD is what makes no sense.
I'm just following Matt's advice here. But it has to do with reducing 
the amount of write operations on the ssd. The more succesful the 
deduping is, the more write operations it will take, and the quicker the 
ssd will wear out, I guess. But I really have no idea of the amount of 
operations that are in play here and what the relative increase in write 
ops is when you turn dedup on. It would be interesting to test/diagnose. 
If there's, say, only a 5% percent increase in write ops when you turn 
on dedup, then its benefits could be interesting enough to turn it on, 
because it could also leave you with extra room on the ssd to compensate 
for the total wear.


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