How many disks in each node? 68? If yes, then change it to 69. Also running
with ec 4+1 is bad for the same reason as running with size=2 min_size=1
which has been mentioned and discussed multiple times on the ML.

On Wed, May 23, 2018, 3:39 AM nokia ceph <[email protected]> wrote:

> Hi David Turner,
>
> This is our ceph config under mon section , we have EC 4+1 and set the
> failure domain as host and osd_min_down_reporters to 4 ( osds from 4
> different host ) .
>
> [mon]
> mon_compact_on_start = True
> mon_osd_down_out_interval = 86400
> mon_osd_down_out_subtree_limit = host
> mon_osd_min_down_reporters = 4
> mon_osd_reporter_subtree_level = host
>
> We have 68 disks , can we increase  sd_min_down_reporters  to 68 ?
>
> Thanks,
> Muthu
>
> On Tue, May 22, 2018 at 5:46 PM, David Turner <[email protected]>
> wrote:
>
>> What happens when a storage node loses its cluster network but not it's
>> public network is that all other osss on the cluster see that it's down and
>> report that to the mons, but the node call still talk to the mons telling
>> the mons that it is up and in fact everything else is down.
>>
>> The setting osd _min_reporters (I think that's the name of it off the top
>> of my head) is designed to help with this scenario. It's default is 1 which
>> means any osd on either side of the network problem will be trusted by the
>> mons to mark osds down. What you want to do with this seeing is to set it
>> to at least 1 more than the number of osds in your failure domain. If the
>> failure domain is host and each node has 32 osds, then setting it to 33
>> will prevent a full problematic node from being able to cause havoc.
>>
>> The osds will still try to mark themselves as up and this will still
>> cause problems for read until the osd process stops or the network comes
>> back up. There might be a seeing for how long an odd will try telling the
>> mons it's up, but this isn't really a situation I've come across after
>> initial testing and installation of nodes.
>>
>> On Tue, May 22, 2018, 1:47 AM nokia ceph <[email protected]>
>> wrote:
>>
>>> Hi Ceph users,
>>>
>>> We have a cluster with 5 node (67 disks) and EC 4+1 configuration and
>>> min_size set as 4.
>>> Ceph version : 12.2.5
>>> While executing one of our resilience usecase , making private interface
>>> down on one of the node, till kraken we saw less outage in rados (60s) .
>>>
>>> Now with luminous, we could able to see rados read/write outage for more
>>> than 200s . In the logs we could able to see that peer OSDs inform that one
>>> of the node OSDs are down however the OSDs  defend like it is wrongly
>>> marked down and does not move to down state for long time.
>>>
>>> 2018-05-22 05:37:17.871049 7f6ac71e6700  0 log_channel(cluster) log
>>> [WRN] : Monitor daemon marked osd.1 down, but it is still running
>>> 2018-05-22 05:37:17.871072 7f6ac71e6700  0 log_channel(cluster) log
>>> [DBG] : map e35690 wrongly marked me down at e35689
>>> 2018-05-22 05:37:17.878347 7f6ac71e6700  0 osd.1 35690 crush map has
>>> features 1009107927421960192, adjusting msgr requires for osds
>>> 2018-05-22 05:37:18.296643 7f6ac71e6700  0 osd.1 35691 crush map has
>>> features 1009107927421960192, adjusting msgr requires for osds
>>>
>>>
>>> Only when all 67 OSDs are move to down state , the read/write traffic is
>>> resumed.
>>>
>>> Could you please help us in resolving this issue and if it is bug , we
>>> will create corresponding ticket.
>>>
>>> Thanks,
>>> Muthu
>>> _______________________________________________
>>> ceph-users mailing list
>>> [email protected]
>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>
>>
>
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