Hi Haung,

So you are suggesting that even though osd.4 in this case has weight 0,
it's still getting new data being written to it? I find that counter to
what weight 0 means.

Thanks
Tarek





From:   huang jun <[email protected]>
To:     Tarek Zegar <[email protected]>
Cc:     Paul Emmerich <[email protected]>, Ceph Users
            <[email protected]>
Date:   06/08/2019 05:27 AM
Subject:        [EXTERNAL] Re: [ceph-users] Reweight OSD to 0, why doesn't
            report degraded if UP set under Pool Size



i think the write data will also write to the osd.4 in this case.
bc your osd.4 is not down, so the ceph don't think the pg have some osd
down,
and it will replicated the data to all osds in actingbackfill set.

Tarek Zegar <[email protected]> 于2019年6月7日周五 下午10:37写道:
  Paul / All

  I'm not sure what warning your are referring to, I'm on Nautilus. The
  point I'm getting at is if you weight out all OSD on a host with a
  cluster of 3 OSD hosts with 3 OSD each, crush rule = host, then write to
  the cluster, it *should* imo not just say remapped but undersized /
  degraded.

  See below, 1 out of the 3 OSD hosts has ALL it's OSD marked out and
  weight = 0. When you write (say using FIO), the PGs *only* have 2 OSD in
  them (UP set), which is pool min size. I don't understand why it's not
  saying undersized/degraded, this seems like a bug. Who cares that the
  Acting Set has the 3 original OSD in it, the actual data is only on 2
  OSD, which is a degraded state

  root@hostadmin:~# ceph -s
  cluster:
  id: 33d41932-9df2-40ba-8e16-8dedaa4b3ef6
  health: HEALTH_WARN
  application not enabled on 1 pool(s)

  services:
  mon: 1 daemons, quorum hostmonitor1 (age 29m)
  mgr: hostmonitor1(active, since 31m)
  osd: 9 osds: 9 up, 6 in; 100 remapped pgs

  data:
  pools: 1 pools, 100 pgs
  objects: 520 objects, 2.0 GiB
  usage: 15 GiB used, 75 GiB / 90 GiB avail
  pgs: 520/1560 objects misplaced (33.333%)
  100 active+clean+remapped

  root@hostadmin:~# ceph osd tree
  ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
  -1 0.08817 root default
  -3 0.02939 host hostosd1
  0 hdd 0.00980 osd.0 up 1.00000 1.00000
  3 hdd 0.00980 osd.3 up 1.00000 1.00000
  6 hdd 0.00980 osd.6 up 1.00000 1.00000
  -5 0.02939 host hostosd2
  1 hdd 0.00980 osd.1 up 0 1.00000
  4 hdd 0.00980 osd.4 up 0 1.00000
  7 hdd 0.00980 osd.7 up 0 1.00000
  -7 0.02939 host hostosd3
  2 hdd 0.00980 osd.2 up 1.00000 1.00000
  5 hdd 0.00980 osd.5 up 1.00000 1.00000
  8 hdd 0.00980 osd.8 up 1.00000 1.00000


  root@hostadmin:~# ceph osd df
  ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP META AVAIL %USE VAR PGS
  STATUS
  0 hdd 0.00980 1.00000 10 GiB 1.7 GiB 765 MiB 12 KiB 1024 MiB 8.2 GiB
  17.48 1.03 34 up
  3 hdd 0.00980 1.00000 10 GiB 1.7 GiB 765 MiB 12 KiB 1024 MiB 8.2 GiB
  17.48 1.03 36 up
  6 hdd 0.00980 1.00000 10 GiB 1.6 GiB 593 MiB 4 KiB 1024 MiB 8.4 GiB 15.80
  0.93 30 up
  1 hdd 0.00980 0 0 B 0 B 0 B 0 B 0 B 0 B 0 0 0 up
  4 hdd 0.00980 0 0 B 0 B 0 B 0 B 0 B 0 B 0 0 0 up
  7 hdd 0.00980 0 0 B 0 B 0 B 0 B 0 B 0 B 0 0 100 up
  2 hdd 0.00980 1.00000 10 GiB 1.5 GiB 525 MiB 8 KiB 1024 MiB 8.5 GiB 15.13
  0.89 20 up
  5 hdd 0.00980 1.00000 10 GiB 1.9 GiB 941 MiB 4 KiB 1024 MiB 8.1 GiB 19.20
  1.13 43 up
  8 hdd 0.00980 1.00000 10 GiB 1.6 GiB 657 MiB 8 KiB 1024 MiB 8.4 GiB 16.42
  0.97 37 up
  TOTAL 90 GiB 15 GiB 6.2 GiB 61 KiB 9.0 GiB 75 GiB 16.92
  MIN/MAX VAR: 0.89/1.13 STDDEV: 1.32
  Tarek Zegar
  Senior SDS Engineer
  Email [email protected]
  Mobile 630.974.7172




  Inactive hide details for Paul Emmerich ---06/07/2019 05:25:23
  AM---remapped no longer triggers a health warning in nautilus. YPaul
  Emmerich ---06/07/2019 05:25:23 AM---remapped no longer triggers a health
  warning in nautilus. Your data is still there, it's just on the

  From: Paul Emmerich <[email protected]>
  To: Tarek Zegar <[email protected]>
  Cc: Ceph Users <[email protected]>
  Date: 06/07/2019 05:25 AM
  Subject: [EXTERNAL] Re: [ceph-users] Reweight OSD to 0, why doesn't
  report degraded if UP set under Pool Size



  remapped no longer triggers a health warning in nautilus.

  Your data is still there, it's just on the wrong OSD if that OSD is still
  up and running.


  Paul

  --
  Paul Emmerich

  Looking for help with your Ceph cluster? Contact us at https://croit.io

  croit GmbH
  Freseniusstr. 31h
  81247 München
  www.croit.io
  Tel: +49 89 1896585 90


  On Thu, Jun 6, 2019 at 10:48 PM Tarek Zegar <[email protected]> wrote:
        For testing purposes I set a bunch of OSD to 0 weight, this
        correctly forces Ceph to not use said OSD. I took enough out such
        that the UP set only had Pool min size # of OSD (i.e 2 OSD).

        Two Questions:
        1. Why doesn't the acting set eventually match the UP set and
        simply point to [6,5] only
        2. Why are none of the PGs marked as undersized and degraded? The
        data is only hosted on 2 OSD rather then Pool size (3), I would
        expect a undersized warning and degraded for PG with data?

        Example PG:
        PG 1.4d active+clean+remapped UP= [6,5] Acting = [6,5,4]

        OSD Tree:
        ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
        -1 0.08817 root default
        -3 0.02939 host hostosd1
        0 hdd 0.00980 osd.0 up 1.00000 1.00000
        3 hdd 0.00980 osd.3 up 1.00000 1.00000
        6 hdd 0.00980 osd.6 up 1.00000 1.00000
        -5 0.02939 host hostosd2
        1 hdd 0.00980 osd.1 up 0 1.00000
        4 hdd 0.00980 osd.4 up 0 1.00000
        7 hdd 0.00980 osd.7 up 0 1.00000
        -7 0.02939 host hostosd3
        2 hdd 0.00980 osd.2 up 1.00000 1.00000
        5 hdd 0.00980 osd.5 up 1.00000 1.00000
        8 hdd 0.00980 osd.8 up 0 1.00000




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--
Thank you!
HuangJun

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