On Thu, Jun 14, 2018 at 4:07 PM Oliver Schulz <[email protected]>
wrote:

> Hi Greg,
>
> I increased the hard limit and rebooted everything. The
> PG without acting OSDs still has none, but I also have
> quite a few PGs with that look like this, now:
>
>      pg 1.79c is stuck undersized for 470.640254, current state
> active+undersized+degraded, last acting [179,154]
>
> I had that problem before (only two acting OSDs on a few PGs),
> I always solved it by setting the primary OSD to out and then
> back in a few seconds later (resulting in a very quick recovery,
> then all was fine again). But maybe that's not the ideal solution?
>
> Here's "ceph pg map" for one of them:
>
>      osdmap e526060 pg 1.79c (1.79c) -> up [179,154] acting [179,154]
>
> I also have two PG's that have only one acting OSD, now:
>
>      osdmap e526060 pg 0.58a (0.58a) -> up [174] acting [174]
>      osdmap e526060 pg 2.139 (2.139) -> up [61] acting [61]
>
> How can I make Ceph assign three OSD's to all of these weird PGs?
> Before the reboot, they all did have three OSDs assigned (except for
> the one that has none), and they were not shown as degraded.
>
>
>  > If it's the second, then fixing the remapping problem will resolve it.
>  > That's probably/hopefully just by undoing the remap-by-utilization
>  > changes.
>
> How do I do that, best? Just set all the weights back to 1.00?
>

Yeah. This is probably the best way to fix up the other undersized PGs — at
least, assuming it doesn't result in an over-full PG!

I don't work with overflowing OSDs/clusters often, but my suspicion is
you're better off with something like CERN's reweight scripts than using
reweight-by-utilization. Unless it's improved without my noticing, that
algorithm just isn't very good. :/
-Greg


>
>
> Cheers,
>
> Oliver
>
>
> P.S.: Thanks so much for helping!
>
>
>
> On 14.06.2018 21:37, Gregory Farnum wrote:
> > On Thu, Jun 14, 2018 at 3:26 PM Oliver Schulz
> > <[email protected] <mailto:[email protected]>>
> wrote:
> >
> >     But the contents of the remapped PGs should still be
> >     Ok, right? What confuses me is that they don't
> >     backfill - why don't the "move" where they belong?
> >
> >     As for the PG hard limit, yes, I ran into this. Our
> >     cluster had been very (very) full, but I wanted the
> >     new OSD nodes to use bluestore, so I updated to
> >     Luminous before I added the additional storage. I
> >     temporarily increased the pg hard limit and after
> >     a while (and after adding the new OSDs) the cluster
> >     seemed to be in a decent state again. Afterwards,
> >     I set the PG hard limit back to normal.
> >
> >     I don't have a "too many PGs per OSD" health warning,
> >     currently - should I still increase the PG hard limit?
> >
> >
> > Well, it's either the hard limit getting hit, or the fact that the PG
> > isn't getting mapped to any OSD and there not being an existing primary
> > to take responsibility for remapping it.
> >
> > If it's the second, then fixing the remapping problem will resolve it.
> > That's probably/hopefully just by undoing the remap-by-utilization
> changes.
> >
> >
> >     On 14.06.2018 20:58, Gregory Farnum wrote:
> >      > Okay, I can’t tell you what happened to that one pg, but you’ve
> got
> >      > another 445 remapped pgs and that’s not a good state to be in. It
> >     was
> >      > probably your use of the rewritten-by-utilization. :/ I am pretty
> >     sure
> >      > the missing PG and remapped ones have the same root cause, and
> it’s
> >      > possible but by no means certain fixing one will fix the others.
> >      >
> >      >
> >      > ...oh, actually, the most likely cause just came up in an
> unrelated
> >      > conversation. You’ve probably run into the pg overdose protection
> >     that
> >      > was added in luminous. Check the list archives for the exact
> >     name, but
> >      > you’ll want to increase the pg hard limit and restart the osds
> that
> >      > exceeded the previous/current setting.
> >      > -Greg
> >      > On Thu, Jun 14, 2018 at 2:33 PM Oliver Schulz
> >      > <[email protected]
> >     <mailto:[email protected]>
> >     <mailto:[email protected]
> >     <mailto:[email protected]>>> wrote:
> >      >
> >      >     I'm not running the balancer, but I did
> reweight-by-utilization
> >      >     a few times recently.
> >      >
> >      >     "ceph osd tree" and "ceph -s" say:
> >      >
> >      > https://gist.github.com/oschulz/36d92af84851ec42e09ce1f3cacbc110
> >      >
> >      >
> >      >
> >      >     On 14.06.2018 20:23, Gregory Farnum wrote:
> >      >      > Well, if this pg maps to no osds, something has certainly
> >     gone wrong
> >      >      > with your crush map. What’s the crush rule it’s using, and
> >     what’s
> >      >     the
> >      >      > output of “ceph osd tree”?
> >      >      > Are you running the manager’s balancer module or something
> >     that
> >      >     might be
> >      >      > putting explicit mappings into the osd map and broken it?
> >      >      >
> >      >      > I’m not certain off-hand about the pg reporting, but I
> >     believe if
> >      >     it’s
> >      >      > reporting the state as unknown that means *no* running osd
> >     which
> >      >      > contains any copy of that pg. That’s not something which
> ceph
> >      >     could do
> >      >      > on its own without failures of osds. What’s the output of
> >     “ceph -s”?
> >      >      > On Thu, Jun 14, 2018 at 2:15 PM Oliver Schulz
> >      >      > <[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>>> wrote:
> >      >      >
> >      >      >     Dear Greg,
> >      >      >
> >      >      >     no, it's a very old cluster (continuous operation
> >     since 2013,
> >      >      >     with multiple extensions). It's a production cluster
> and
> >      >      >     there's about 300TB of valuable data on it.
> >      >      >
> >      >      >     We recently updated to luminous and added more OSDs (a
> >     month
> >      >      >     ago or so), but everything seemed Ok since then. We
> >     didn't have
> >      >      >     any disk failures, but we had trouble with the MDS
> daemons
> >      >      >     in the last days, so there were a few reboots.
> >      >      >
> >      >      >     Is it somehow possible to find this "lost" PG again?
> Since
> >      >      >     it's in the metadata pool, large parts of our CephFS
> >     directory
> >      >      >     tree are currently unavailable. I turned the MDS
> >     daemons off
> >      >      >     for now ...
> >      >      >
> >      >      >
> >      >      >     Cheers
> >      >      >
> >      >      >     Oliver
> >      >      >
> >      >      >     On 14.06.2018 19:59, Gregory Farnum wrote:
> >      >      >      > Is this a new cluster? Or did the crush map change
> >     somehow
> >      >      >     recently? One
> >      >      >      > way this might happen is if CRUSH just failed
> >     entirely to
> >      >     map a pg,
> >      >      >      > although I think if the pg exists anywhere it
> >     should still be
> >      >      >     getting
> >      >      >      > reported as inactive.
> >      >      >      > On Thu, Jun 14, 2018 at 8:40 AM Oliver Schulz
> >      >      >      > <[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>
> >      >      >     <mailto:[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>>
> >      >      >     <mailto:[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>
> >      >      >     <mailto:[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>>>> wrote:
> >      >      >      >
> >      >      >      >     Dear all,
> >      >      >      >
> >      >      >      >     I have a serious problem with our Ceph cluster:
> >     One of our
> >      >      >     PGs somehow
> >      >      >      >     ended up in this state (reported by "ceph
> >     health detail":
> >      >      >      >
> >      >      >      >           pg 1.XXX is stuck inactive for ...,
> current
> >      >     state unknown,
> >      >      >      >     last acting []
> >      >      >      >
> >      >      >      >     Also, "ceph pg map 1.xxx" reports:
> >      >      >      >
> >      >      >      >           osdmap e525812 pg 1.721 (1.721) -> up []
> >     acting []
> >      >      >      >
> >      >      >      >     I can't use "ceph pg 1.XXX query", it just
> >     hangs with
> >      >     no output.
> >      >      >      >
> >      >      >      >     All OSDs are up and in, I have MON quorum, all
> >     other
> >      >     PGs seem
> >      >      >     to be
> >      >      >      >     fine.
> >      >      >      >
> >      >      >      >     How can diagnose/fix this? Unfortunately, the
> PG in
> >      >     question
> >      >      >     is part
> >      >      >      >     of the CephFS metadata pool ...
> >      >      >      >
> >      >      >      >     Any help would be very, very much appreciated!
> >      >      >      >
> >      >      >      >
> >      >      >      >     Cheers,
> >      >      >      >
> >      >      >      >     Oliver
> >      >      >      >     _______________________________________________
> >      >      >      >     ceph-users mailing list
> >      >      >      > [email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>
> >     <mailto:[email protected] <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>>
> >      >      >     <mailto:[email protected]
> >     <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>
> >     <mailto:[email protected] <mailto:[email protected]>
> >      >     <mailto:[email protected]
> >     <mailto:[email protected]>>>>
> >      >      >      >
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >      >      >      >
> >      >      >
> >      >
> >
>
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