F20 System Wide Change: SSD cache

[DJ Delorie]

I think this is a bad idea, at least for my setup.  I really don't
want my small expensive boot SSD being beaten to death trying to cache
a multi-terabyte array, especially since I have plenty of RAM that
already serves that purpose (the machine rarely reboots).

At the very least, this feature should be disabled if the SSD is the
boot/root drive.  When SSDs fail, they fail completely, and it's
irresponsible to cause early failure on a drive that's critical for
booting and OS operation.

Also, I think such features should be postponed until/unless there's a
clear and obvious way to configure/disable them that doesn't involve
installing additional packages or editing obscure text files.