Anyone using Facebook's flashcache?

[AJ]

With big data requirements pressuring me to pack up to a terabyte on one 
node, I suspect that even 32 GB of RAM just will not be large enough for 
Cass' various memory caches to be effective.  32/1000 is a tiny working 
set to data store ratio... even assuming non-random reads.  So, I'm 
investigating whether or not a 256 GB SSD used as a cache between the 
data HDD and the Cass server process.  It won't decrease cache misses, 
but at least the access time would be orders of magnitude faster than 
from the hdd.  Also, write performance is improved because of lazy flushing.

Do any Cass developers have any thoughts on this and whether or not it 
would be helpful considering Cass' architecture and operation?

Links:
http://www.facebook.com/note.php?note_id=388112370932
https://github.com/facebook/flashcache/wiki

aj