crush rule definitions

[Zenon Panoussis <oracle@provocation.net>]

Hi

I thought that min_size in crush is obvious, but the more I read the more
I tend to doubt. So I might as well ask:

With a crushmap like this

===
type 0 device
type 1 host
type 2 root

[definitions for the above; hosts contain devices, root contains hosts]

rule data {
        ruleset 0
        type replicated
        min_size 2
        max_size 2
        step take root
        step chooseleaf firstn 0 type host
        step emit
}
===

does "min_size 2, max_size 2" mean that I want "2 copies of the data on each
host" or "2 copies of the data in total in the entire cluster"?

Z