[linux-elitists] A modest proposal: SSD disk acceleration in kernel.

Rick Moen rick@linuxmafia.com
Fri Oct 24 16:01:24 PDT 2008


Quoting Ruben Safir (ruben@mrbrklyn.com):

> Hard drives don't last forever either and certainly the hysical parts
> wear out.  How do they compare?

Using filesystems developed for magnetic media, historically speaking,
NAND flash has done badly enough, relatively speaking, that I've been
reluctant to rely on it for any deployment where writes are involved
(even if only atime stamps).

The key to understanding the problem is to realise that, for even one
bit in a sector to change, a NAND device has to put that entire sector
through an erase/write cycle.  When the sector has racked up a
sufficient number of those cycles, it wears out.  (If you're lucky, 
it'll get mapped out at the hardware level and something else will have
transparently gotten its dataset.  If not, and the sector's something
vital, you can lose the device.)

Above are very general observations, necessarily.

-- 
Cheers,              But then voting season comes, and reminds you that all 
Rick Moen            those Americans that are individually sane and normal tend
rick@linuxmafia.com  to be collectively crazy and very odd. -- Linus Torvalds
      http://torvalds-family.blogspot.com/2008/10/stranger-in-strange-land.html



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