ceph/src/crush/sample.txt

# devices
device 1 osd001
device 2 osd002
device 3 osd003 down   # same as offload 1.0
device 4 osd004 offload 0       # 0.0 -> normal, 1.0 -> failed
device 5 osd005 offload 0.1
device 6 osd006 offload 0.1

# hierarchy
type 0 osd   # 'device' is actually the default for 0
type 2 cab
type 3 row
type 10 pool

cab root {
       id -1         # optional
       alg tree     # required
       item osd001
       item osd002 weight 600 pos 1
       item osd003 weight 600 pos 0
       item osd004 weight 600 pos 3
       item osd005 weight 600 pos 4
}

# rules
rule normal {
     # these are required.
     pool 0
     type replicated 
     min_size 1
     max_size 4
     # need 1 or more of these.
     step take root
     step choose firstn 0 type osd
     step emit
}

rule {
     pool 1
     type erasure
     min_size 3
     max_size 6
     step take root
     step choose indep 0 type osd
     step emit
}