> Is it possible to configure crush map such that it will tolerate "room" > failure? In my case, there is one > network switch per room and one power supply per room, which makes a single > point of (room) failure.
Hi, You cannot achieve real room redundancy with just two rooms. At minimum you'll need a third room (witness) from which you'll need independent network connections to the two server rooms. Otherwise it's impossible to have monitor quorum when one of the two rooms fails. And then you'd need to consider osd redundancy. You could do with replica size = 4, min_size = 2 (or any min_size = n, size = 2*n ), but that's not perfect as you lose exactly half of the replicas in case of a room failure. If you were able to use EC-pools you'd have more options with LRC coding (http://docs.ceph.com/docs/master/rados/operations/erasure-code-lrc/). We run ceph in a 3 room configuration with 3 monitors, size=3, min_size=2. It works, but it's not without hassle either. -- Eino Tuominen _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
