[HN Gopher] Wear leveling in SSDs considered harmful
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       Wear leveling in SSDs considered harmful
        
       Author : matt_d
       Score  : 33 points
       Date   : 2022-06-27 20:39 UTC (2 hours ago)
        
 (HTM) web link (dl.acm.org)
 (TXT) w3m dump (dl.acm.org)
        
       | rhacker wrote:
       | Great so ten years from now after all the manufacturers remove
       | this feature we'll have articles saying that the missing wear
       | leveling feature is causing data loss and early failures.
        
       | dontbenebby wrote:
       | There's a whole attack paper on how excessive writes can be
       | harmful, so I suspect trying to reduce them is better than
       | nothing:
       | 
       | https://www.usenix.org/system/files/conference/hotsec12/hots...
       | 
       | (I'm not an EE expert by any stretch, but that paper cites
       | several peer reviewed wear leveling techniques.)
       | 
       | The REAL issue, based on my (amateur) reading, is that the
       | components that handle wear leveling are not open source:
       | 
       | > _In all cases commercially available flash controllers provide
       | no details of the internal mechanisms that are used to extend
       | life, as such details remain the competitive advantage in a
       | crowded market space_
       | 
       | We are sitting around trying to make inferences about
       | proprietary, unpublished algorithms that have very real effects
       | on people, not just property, when what we probably want is for
       | industry to collaborate on figuring out which techniques work
       | best rather than hoarding that knowledge and forcing folks to get
       | burned once or twice or pay exorbitant amounts of money for
       | research grants to infer what purchasing decisions to make.
        
       | wtallis wrote:
       | Rather silly title, but that's true of many papers reusing this
       | meme.
       | 
       | The abstract presents an alternative to wear leveling that they
       | refer to as "capacity variance", also known as _breaking
       | compatibility with all previous filesystems, drivers, and
       | bootloaders_. Wear leveling has been a necessary evil, because
       | without it flash storage simply would not be usable _at all_ as
       | hard drive replacements /successors. Nowadays _some_ of the
       | pieces are in place to allow software to interact with SSDs in a
       | more natural fashion, but it still isn 't possible to completely
       | forego the FTL that emulates hard drive behavior.
        
         | cma wrote:
         | FTL == flash translation layer
        
         | shagie wrote:
         | > Rather silly title, but that's true of many papers reusing
         | this meme.
         | 
         | "Considered Harmful" Essays Considered Harmful -
         | https://meyerweb.com/eric/comment/chech.html //
         | https://news.ycombinator.com/item?id=9744916 (from 2015, other
         | posts didn't gain much traction)
        
         | remram wrote:
         | The best I can say if I get an article titled "Wear leveling
         | considered harmful" is say "no, it's not".
         | 
         | "Considered harmful" is appropriate for a PSA that the whole
         | community considers something to be harmful. It's terrible for
         | an essay trying to argue that it _should be_ avoided even
         | though that is _not the community standard_ (yet).
         | 
         | The title should be "Why wear leveling is harmful", "A case
         | against wear leveling", or something similar. I don't
         | understand why people keep using those stupid titles.
        
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       (page generated 2022-06-27 23:01 UTC)