solid state drives?

RW rwmaillists at
Fri Aug 22 19:21:12 UTC 2014

On Fri, 22 Aug 2014 12:41:57 -0400 (EDT)
Daniel Feenberg wrote:

> > A typical modern 120GB MLC SSD will have a specified write
> > endurance of around 8TB which is equivalent to  1GB a day for 22
> > years. They should be fine for most things where there's nothing
> > doing heavy duty writing.
> I sort of understand that - but does the SSD have the ability to move 
> unchanged data around to even out the wear? 

It's called static wear-levelling. I think it's the norm on enterprise
grade SSDs, but it's rarely mentioned in the specs of domestic grade

> That is, if I fill the
> drive with 100GB of never changing files, and then write lots of
> frequently changing files to the last 20GB, does this put all the
> wear on a small portion of the drive, while most of the drive suffers
> no wear at all?

Without static wear-levelling it's advisable to leave a sizeable
fraction of the drive unused. With trim support that can be inside the
filesystem, without it the partitioning should not fill the whole drive.

OS files tend to get deleted several times a year during updates, so
they aren't so much of a problem, if you have trim support.

BTW GELI doesn't support trim, so you have to have some free space
outside an encrypted partition. 

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