Re: ceph replication and data redundancy

[Wido den Hollander <wido@widodh.nl>]

On 01/21/2013 02:08 PM, Joao Eduardo Luis wrote:
> On 01/21/2013 08:14 AM, Ulysse 31 wrote:
>> Hi everybody,
>>
>> In fact, i found searching the doc on section "adding/removing a
>> monitor", infos about the paxos system used for quorum establishment.
>> Following the documentation, in a catastrophy scenario, i need to
>> remove the other monitors configured on the other buildings.
>> For better efficiency, i think i'll keep 1 monitor per building, and,
>> if two other building fails, i will delete those two monitors from the
>> configuration in order to access data again.
>> I'll simulate that and see if it goes well.
>> Thanks for your help and advices.
>
> If you are set on that approach, you could just as well add a third
> monitor on one of the buildings (whichever you feel to be more
> resilient), and cut down the chances of an unavailable cluster if the
> other fails.
>
> It doesn't solve your problem, but if the building with just one monitor
> fails, your cluster will still be available; if it's the other way
> around, you could do the manual recovery just the same anyway.
>

Another approach, if possible try to add a 3rd monitor in a "neutral" place.

I for sure don't know how your network looks like, but you might be able 
to put up a monitor in an external datacenter and do something with a VPN?

Assuming both buildings have their own external internet connection.

Wido

>    -Joao
>