Depending on the kernel version you may be missing some features required by the cluster (or vice versa, required by client but not available on the cluster). Hence the errors "feature set mismatch".
Some examples of errors that can be encountered :
mon0 192.168.0.1:6789 feature set mismatch …Il you just upgrade to Ceph 0.75, you can see this message :
$ ceph health HEALTH_WARN crush map has non-optimal tunables
For more explanation, everything is explained in the documentation: http://ceph.com/docs/master/rados/operations/crush-map/#warning-when-tunables-are-non-optimal
Before doing this, read the documentation !
$ ceph osd crush tunables optimal …I take opportunity to the new kernel release 3.10.26 to advise the person using the client rbd kernel update to this version. Indeed a number of fixes have been applied to this version making use of rbd kernel particularly stable.
http://kernel.org
Patches applied :
Josh Durgin <josh …It is not mandatory to install Ceph binaries (especially ceph-common) to be able to map a Rbd blocdevice you can also use the kernel path /sys/bus/rbd provided by rbd module.
$ modprobe rbd
$ echo "192.168.0.1,192.168.0.2,192.168.0.3 name=admin,secret …ceph health
HEALTH_WARN 1 near full osd(s)
Arrhh, Trying to optimize a little weight given to the OSD. Rebalancing load between osd seems to be easy, but do not always go as we would like...
Before operation get the map of Placement Groups.
$ ceph pg dump …