• set osd with ‘noout’ so that the data will not migrate

ceph osd set noout

• stop osd which need resize journal

service ceph stop osd.N

• flush his journal to the filestore

ceph-osd -i N --flush-journal

• reconfigure the journal config and resize

journal_uuid=$(sudo cat /var/lib/ceph/osd/ceph-N/journal_uuid)

sgdisk --new=0:0:+20480M --change-name=0:'ceph journal' --partition-guid=0:$journal_uuid --typecode=0:$journal_uuid --mbrtogpt -- /dev/sdx

• initialize the new journal

ceph-osd -i N --mkjournal

• restart the osd

service ceph start osd.N

• reset ‘noout’ flag

ceph osd unset noout