Replying to myself, and for the benefit of other caffeine-starved people:
Setting the last rule to "chooseleaf firstn 0" does not generate the
desired results, and ends up sometimes putting all replicas in the same
zone.
I'm slowly getting the hang of customised crushmaps ;-)
On 16/09/14 18:39, Daniel Swarbrick wrote:
>
> One other area I wasn't sure about - can the final "chooseleaf" step
> specify "firstn 0" for simplicity's sake (and to automatically handle a
> larger pool size in future) ? Would there be any downside to this?
>
> Cheers
>
> On 16/09/14 16:20, Loic Dachary wrote:
>> Hi Daniel,
>>
>> When I run
>>
>> crushtool --outfn crushmap --build --num_osds 100 host straw 2 rack straw 10 default straw 0
>> crushtool -d crushmap -o crushmap.txt
>> cat >> crushmap.txt <<EOF
>> rule myrule {
>> ruleset 1
>> type replicated
>> min_size 1
>> max_size 10
>> step take default
>> step choose firstn 2 type rack
>> step chooseleaf firstn 2 type host
>> step emit
>> }
>> EOF
