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 …Howto add support of rbd device on debian wheezy.
Since wheezy, libvirt supports rbd device.
If you do not add the support in qemu-kvm you may have an error like this:
error: Failed to start domain ubuntu
error: internal error process exited while connecting to monitor: char device …Lets take a look how rbd object are store on rados and the difference between format 1 and format 2.
$ rbd create myrbd --size=10
$ rados ls -p rbd
myrbd.rbd
rbd_directory
$ rbd map myrbd
$ dd if=/dev/zero of=/dev/rbd/rbd/myrbd
$ rados ls -p rbd …Some common problems when adding a monitor to an existing cluster, for example if config is not found :
$ service ceph start mon.ceph-03
/etc/init.d/ceph: mon.ceph-03 not found (/etc/ceph/ceph.conf defines osd.2 , /var/lib/ceph defines osd.2)
If you do not …
Use command "rbd du"
$ rbd du rbd/myrbd
NAME PROVISIONED USED
myrbd 4 TiB 1023 GiB
To get the real size used by a rbd image :
rbd diff $POOL/$IMAGE | awk '{ SUM += $2 } END { print SUM/1024/1024 " MB" }'
For exemple …