Your customer has designated a number of database objects to be kept persistently in the
Exadata Smart Flash Cache. What happens if the total size of these objects is greater than 80% of
the size of the available Exadata Smart Flash Cache?
A.
Nothing
B.
Exadata Smart Flash Cache expands the allocation to hold the objects.
C.
Not all objects will be stored in Exadata Smart Flash Cache.
D.
Overall performance is increased as more objects fit into Exadata Smart Flash Cache.
Explanation:
We have 3 possible values for CELL_FLASH_CACHE : DEFAULT (the default),
KEEP and NONE. Keep means that the sales table will be stored in the Flash Cache “more
aggressively” than the default.
in the Flash Cache, KEEP assigned objects are also subject to an age out policy – if those objects
ain’t accessed for a longer time, they will vanish from the flash cache to make room for objects
with the default attribute. And yes, they cannot consume more than 80 % of the Flash Cache. If
you assign objects with in summary more than 80 % of the Flash Cache with the
CELL_FLASH_CACHE KEEP attribute – they will simply not all be flash cached – at the same
time.
http://uhesse.wordpress.com/2011/02/02/exadata-part-iv-flash-cache/