# ceph-osd -i 0 --mkfs --mkkey
2015-05-22 11:47:39.764248 7f44025ec800 -1 journal FileJournal::_open: aio not supported without directio; disabling aio
2015-05-22 11:47:41.220722 7f44025ec800 -1 filestore(/var/lib/ceph/osd/ceph-0) FileStore::mount : error in _list_snaps: (2) No such file or directory
2015-05-22 11:47:41.220739 7f44025ec800 -1 OSD::mkfs: couldn't mount ObjectStore: error -2
2015-05-22 11:47:41.220782 7f44025ec800 -1  ** ERROR: error creating empty object store in /var/lib/ceph/osd/ceph-0: (2) No such file or directory