[ceph-users] Another OSD broken today. How can I recover it?

Ronny Aasen ronny+ceph-users at aasen.cx
Tue Dec 5 06:32:17 PST 2017


On 05. des. 2017 10:26, Denes Dolhay wrote:
> Hi,
> 
> This question popped up a few times already under filestore and 
> bluestore too, but please help me understand, why this is?
> 
> "when you have 2 different objects, both with correct digests, in your 
> cluster, the cluster can not know witch of the 2 objects are the correct 
> one."
> 
> Doesn't it use an epoch, or an omap epoch when storing new data? If so 
> why can it not use the recent one?
> 
> 


this have been discussed a few times on the list. generally  you have 2 
disks.

first disk fail. and writes happen to the other disk..

first disk recovers, and second disk fail before recovery is done. 
writes happen to second disk..

all objects have correct checksum. and both osd's think they are the 
correct one. so your cluster is inconsistent.  so bluestore checksums
does not solve this problem, both objects are objectivly "correct" :)


with min_size =2 the cluster would not accept a write unless 2 disks 
accepted the write.

kind regards
Ronny Aasen




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