On Tue, 31 Mar 2015 02:42:27 AM Kai KH Huang wrote: > Hi, all > I have a two-node Ceph cluster, and both are monitor and osd. When > they're both up, osd are all up and in, everything is fine... almost: Two things. 1 - You *really* need a min of three monitors. Ceph cannot form a quorum with just two monitors and you run a risk of split brain. 2 - You also probably have a min size of two set (the default). This means that you need a minimum of two copies of each data object for writes to work. So with just two nodes, if one goes down you can't write to the other. So: - Install a extra monitor node - it doesn't have to be powerful, we just use a Intel Celeron NUC for that. - reduce your minimum size to 1 (One). _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com