One customer want to achieve this specific setup in ODF : 

pool0 => osd.0, osd.1, osd.2 # latency sentive pool

pool1 => osd.3, osd.4, osd.5 # general purpose pool

pool2 => osd.3, osd.4, osd.5 # another general purpose pool

Let's say pool0 will be used for rbd service for a given application which is really time sensitive and should not be too much disturb by other application running on top of other pool.

And pool1 and pool2 will be used by a second set of application which has really lower latency sensitivity constraint.

The whole idea behind this need is to get more guarantee on R/W performance and on the latency.

This can be achieve by some CRUSH on ceph, but on ODF side, it seem there is no knob to achieve this goal.