Replacing Drive with SSD

Brandon J. Wandersee brandon.wandersee at
Sun Sep 6 16:26:54 UTC 2015

Warren Block writes:

> The SSD keeps a map of which blocks have been written.  So writing just 
> once with dd is not a wear problem.  The problem is that now the SSD has 
> no way of knowing whether that block has real data on it or not.  So it 
> can't swap it for wear leveling.  That's what trim does--when a file is 
> deleted, the filesystem uses trim to notify the SSD that those blocks 
> are no longer in use.

Would this also apply to a *single file* written using dd? Your SSD
guide recommends creating a swap file from /dev/zero using dd:

> Because the data goes through the file system, TRIM will be used, and
> the swap file can be resized without repartitioning the SSD.

So is the problem with dd and SSDs only relevant when targeting a whole
block device?

   		      :: Brandon Wandersee ::
                  :: brandon.wandersee at ::
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