> (Adding back the list)
I had written privately on purpose. > >> https://docs.clyso.com/docs/kb/rados/#osd---improved-procedure-for-adding-hosts-or-osds >> >> <https://docs.clyso.com/docs/kb/rados/#osd---improved-procedure-for-adding-hosts-or-osds> > > Is the upstream source for `upmap-remapped.py` the `ceph-scripts` repo? > > If yes, is it known why there are 2 different places for `ceph-scripts` > (Gitlab and Github), with diverged histories, both of which are recently > edited, by the same individuals? > > https://github.com/cernceph/ceph-scripts/commits/master/tools/upmap/upmap-remapped.py > https://gitlab.cern.ch/ceph/ceph-scripts/-/commits/master/tools/upmap/upmap-remapped.py I will defer to Dan van der Ster on that. > >> If I understand what you’re getting at, I don’t think that’s the case. I >> *think* recent releases give priority to undersized / degraded PGs over >> remapped PGs. > > It's not really `degraded` vs `misplaced` I'm getting at. > > But instead, consider this scneario: > > We have > > * osd.1 (very full, 100 GB free) > * osd.2 (very full, 100 GB free) > * osd.30 (empty) > > and we have > > * PGa on osd.1, which Ceph now wants to be on osd.2 > * PGb on osd.2, which Ceph now wants to be on osd.30 > > The simple thing that could theoretically be done is that simultaneously be > done is that the PGa (osd.1 -> osd.2) move, and the PGb (osd2. -> osd.30) > move, are started immediately and run in parallel. > > But I suspect that what Ceph does is to make decisions on PG granularity: > > 1. See that there's no space on osd.2 for PGa, thus not start the move. > 2. Move PGb from osd.2 to osd.30. Wait until that's done (takes long if PGs > are large). > 3. See that now there enough space on osd.2 for PGa, thus only now start the > move. > > Is this really what happens? Yes, backfill will not proceed to an OSD that is past the backfillful threshold. It’s also the case that the cluster usually cannot sustain all backfill / recovery ops at the same time; there are priority mechanisms as well as various throttles to avoid a thundering herd DoSing client ops. I will have to defer to the source and devs for the particulars of that process, as it has evolved over time. > > Thanks! _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
