[PVE-User] Ris: Ceph MON quorum problem

[Ronny Aasen]

with 2 rooms there is no way to avoid a split brain situation unless you 
have a tie breaker outside one of those 2 rooms.

Run a Mon on a neutral third location is the quick, correct, and simple 
solution.

Or

you need to have a master-slave situation where one room is the master 
(3 mons) and the other room is the slave (2 mons) and the slave can not 
operate without the master, but the master can operate alone.

good luck
Ronny


On 14.09.2019 16:11, f.cuseo at panservice.it wrote:
> This is My last choice :)
> Inviato dal mio dispositivo Huawei
> -------- Messaggio originale --------
> Oggetto: Re: [PVE-User] Ceph MON quorum problem
> Da: "Brian :"
> A: Fabrizio Cuseo ,PVE User List
> CC:
> 
> 
> Have a mon that runs somewhere that isn't either of those rooms.
> 
> On Friday, September 13, 2019, Fabrizio Cuseo <f.cuseo at panservice.it> wrote:
>> Hello.
>> I am planning a 6 hosts cluster.
>>
>> 3 hosts are located in the CedA room
>> 3 hosts are located in the CedB room
>>
>> the two rooms are connected with a 2 x 10Gbit fiber (200mt) and in each
> room i have 2 x 10Gbit stacked switch and each host have a 2 x 10Gbit (one
> for each switch) for Ceph storage.
>>
>> My need is to have a full redundancy cluster that can survive to CedA (or
> CedB) disaster.
>>
>> I have modified the crush map, so I have a RBD Pool that writes 2 copies
> in CedA hosts, and 2 copies in CedB hosts, so a very good redundancy (disk
> space is not a problem).
>>
>> But if I loose one of the rooms, i can't establish the needed quorum.
>>
>> Some suggestion to have a quick and not too complicated way to satisfy my
> need ?
>>
>> Regards, Fabrizio
>>
>>
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