stripe cache question

Hi all,

few posts ago was mentioned that the unit of the stripe
cache are "pages per device", usually 4K pages.

Questions:

1) Does "device" means raid (md) device or component
device (HDD)?

2) The max possible value seems to be 32768, which
means, in case of 4K page per md device, a max of
128MiB of RAM.
Is this by design? Would it be possible to increase
up to whatever is available?

Thanks,

bye,

-- 

piergiorgio