On Fri, Apr 5, 2013 at 10:28 AM, Dimitri Maziuk <dmaziuk@xxxxxxxxxxxxx> wrote: > On 04/05/2013 10:12 AM, Wido den Hollander wrote: > >> Think about it this way. You have two racks and the network connection >> between them fails. If both racks keep operating because they can still >> reach that single monitor in their rack you will end up with data >> inconsistency. > > Yes. In DRBD land it's called 'split brain' and they have (IIRC) entire > chapter in the user manual about picking up the pieces. It's not a new > problem. > >> You should place mon.c outside rack A or B to keep you up and running in >> this situation. > > It's not about racks, it's about rooms, but let's say rack == room == > colocation facility. And I have two of those. > > Are you saying I need a 3rd colo with all associated overhead to have a > usable replica of my data in colo #2? Or just a VM running somewhere that's got a VPN connection to your room-based monitors, yes. Ceph is a strongly consistent system and you're not going to get split brains, period. This is the price you pay for that. -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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