On Mon, Aug 20, 2018 at 1:28 PM, Luk <skidoo@xxxxxxx> wrote:
> Hello,
>
> I have following definition in crushmap:
>
> rule default.rgw.buckets.data {
> id 10
> type erasure
> min_size 3
> max_size 24
> step set_chooseleaf_tries 5
> step set_choose_tries 100
> step take default
> step chooseleaf indep 0 type osd
> step emit
> }
>
> 'step chooseleaf indep 0 type osd` which I changed from:
> 'step chooseleaf indep 0 type host'
>
> but I used following profile to create pool:
>
> crush-device-class=
> crush-failure-domain=host
> crush-root=default
> jerasure-per-chunk-alignment=false
> k=6
> m=6
> plugin=jerasure
> technique=reed_sol_van
> w=8
>
> how crush-failure-domain from EC profile is related to rule from
> crushmap ?
The failure domain specified in the EC profile is used to specify the
type of CRUSH bucket the chooseleaf command operates on. If the
failure domain is set to host, CRUSH will select independent hosts for
each OSD in a PG. As you've reconfigured it, CRUSH will just select
the requisite number of OSDs without worrying about they're on
independent machines — that is a terrible idea, as you have no
resiliency against hardware failures!
-Greg
>
>
> --
> Regards,
> Luk
>
