GEOM mentor request

[Warren Block]

On Fri, 1 Nov 2013, symbolics at gmx.com wrote:

>  + Implement new things. Some ideas I have had:
>    + GEOM "ERASE" - Rewrite deletes into random writes.
>    + GEOM "PLUG" - Persistent version of the connect/disconnect verbs
>      where the flag sits in the class metadata. This might be a cleaner
>      approach, rather than adding the verbs to all the existing
>      providers.
>    + GEOM "TAP" - Allow userspace processes to hook into the GEOM
>      API. Intended for debugging and development.
>    + GEOM "WCACHE" - Allow you to use small, fast provider as a buffer
>      for a larger, slower provider.
>    + GEOM DTrace provider. Provide GEOM specific probes to complement
>      the IO provider.
>  + Probably other bits I can't remember right now.

How about an explicit geom retaste command?  "true > /dev/ada0" is
misleading to the reader.

Also, a RAM-cached version of gmirror that would report writes finished 
as soon as the faster drive finishes.  Kind of the opposite of the 
WCACHE above.  This would permit creating mirrors of an SSD and hard 
drive without performance loss, at least up until available write 
buffer space runs out.  This one may not be so easy.