Re: [ceph-users] degraded objects after osd add

2016-11-23 Thread Kevin Olbrich
Hi,

what happens when size = 2 and some objects are in degraded state?
This sounds like easy data loss when the old but active OSD fails while
recovery is in progress?

It would make more sense to have the pg replicate first and then remove the
PG from the old OSD.

Mit freundlichen Grüßen / best regards,
Kevin Olbrich.

>
>  Original Message 
> Subject: Re: [ceph-users] degraded objects after osd add (17-Nov-2016 9:14)
> From:Burkhard Linke <burkhard.li...@computational.bio.uni-giessen.de>
> To:  c...@dolphin-it.de
>
> Hi,
>
>
> On 11/17/2016 08:07 AM, Steffen Weißgerber wrote:
> > Hello,
> >
> > just for understanding:
> >
> > When starting to fill osd's with data due to setting the weigth from 0
> to the normal value
> > the ceph status displays degraded objects (>0.05%).
> >
> > I don't understand the reason for this because there's no storage
> revoekd from the cluster,
> > only added. Therefore only the displayed object displacement makes sense.
> If you just added a new OSD, a number of PGs will be backfilling or
> waiting for backfilling (the remapped ones). I/O to these PGs is not
> blocked, and thus object may be modified. AFAIK these objects show up as
> degraded.
>
> I'm not sure how ceph handles these objects, e.g. whether it writes them
> to the old OSDs assigned to the PG, or whether they are put on the new OSD
> already, even if the corresponding PG is waiting for backfilling.
>
> Nonetheless the degraded objects will be cleaned up during backfilling.
>
> Regards,
> Burkhard
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>
>
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Re: [ceph-users] degraded objects after osd add

2016-11-17 Thread Burkhard Linke

Hi,


On 11/17/2016 08:07 AM, Steffen Weißgerber wrote:

Hello,

just for understanding:

When starting to fill osd's with data due to setting the weigth from 0 to the 
normal value
the ceph status displays degraded objects (>0.05%).

I don't understand the reason for this because there's no storage revoekd from 
the cluster,
only added. Therefore only the displayed object displacement makes sense.
If you just added a new OSD, a number of PGs will be backfilling or 
waiting for backfilling (the remapped ones). I/O to these PGs is not 
blocked, and thus object may be modified. AFAIK these objects show up as 
degraded.


I'm not sure how ceph handles these objects, e.g. whether it writes them 
to the old OSDs assigned to the PG, or whether they are put on the new 
OSD already, even if the corresponding PG is waiting for backfilling.


Nonetheless the degraded objects will be cleaned up during backfilling.

Regards,
Burkhard
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