It generally means, in CS terms, that you have a graph rather than a tree. In other words, you have two roots, or other crush buckets, which contain some of the same buckets/items underneath themselves. On Fri, Oct 1, 2021 at 9:43 AM Harry G. Coin <hgcoin@xxxxxxxxx> wrote: > > I asked as well, it seems nobody on the list knows so far. > > > On 9/30/21 10:34 AM, Andrew Gunnerson wrote: > > Hello, > > > > I'm trying to figure out what overlapping roots entails with the default > > scale-down autoscaling profile in Ceph Pacific. My test setup involves a CRUSH > > map that looks like: > > > > ID=-1 | root=default > > ID=-58 | rack=rack1 > > ID=-70 | host=ssd-1 > > | <OSDs> > > ID=-61 | rack=rack2 > > ID=-55 | host=ssd-2 > > | <OSDs> > > ID=-62 | rack=rack3 > > ID=-52 | host=ssd-3 > > | <OSDs> > > ID=-63 | rack=rack4 > > ID=-19 | host=hdd-1 > > | <OSDs> > > | <15 more hosts> > > > > The CRUSH rules I created are: > > > > # Rack failure domain for SSDs > > ceph osd crush rule create-replicated replicated_ssd default rack ssd > > # Host failure domain for HDDs > > ceph osd crush rule create-replicated replicated_hdd default host hdd > > ceph osd erasure-code-profile set erasure_hdd ruleset k=3 m=2 crush-device-class=hdd crush-failure-domain=host > > > > and the pools are: > > > > Pool | CRUSH rule/profile | Overlapped roots error > > ---------------------------|--------------------|----------------------- > > device_health_metrics | replicated_rule | -1 (root=default) > > cephfs_metadata | replicated_ssd | -51 (root=default~ssd) > > cephfs_data_replicated_ssd | replicated_ssd | -51 (root=default~ssd) > > cephfs_data_replicated_hdd | replicated_hdd | -2 (root=default~hdd) > > cephfs_data_erasure_hdd | erasure_hdd | -1 (root=default) > > > > With this setup, the autoscaler is getting disabled in every pool with the > > following error: > > > > [pg_autoscaler WARNING root] pool <num> contains an overlapping root -<id>... skipping scaling > > > > There doesn't seem to be much documentation about overlapped roots. I think I'm > > fundamentally not understanding what it means. Does it mean that the autoscaler > > can't handle two different pools using OSDs under the same (shadow?) root in the > > CRUSH map? > > > > Is this setup something that's not possible using the scale-down autoscaler > > profile? It seems that the scale-up profile doesn't have a concept of overlapped > > roots. > > > > Thank you, > > Andrew > > _______________________________________________ > > ceph-users mailing list -- ceph-users@xxxxxxx > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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