Why is SU+J undesirable on SSDs?

[Brett Glass]

At 04:32 PM 11/3/2012, Karl Denninger wrote:

>It is utter insanity to enable, by default, filesystem options 
>that break the canonical backup solution in the handbook ("dump", 
>when used with "-L", which it must be to dump a live filesystem SAFELY.)

I have not used "dump" in many, many years. So, I hope the 
installer will not make it difficult for me to turn on SU+J despite 
the problem you mention above.

That being said, "dump" should obviously be fixed to work with 
SU+J. Perhaps there could be a workaround (e.g. synchronizing the 
file system and temporarily turning off journaling during a backup) 
that would eliminate the need to turn SU+J off all the time while a 
more graceful fix is being readied.

--Brett