/dev/sdc — HDD
/dev/sdm — SSD с несколькими разделами, на первом стоит ОС (Ubuntu Server 16.04.3 LTS, ceph 12.2.0 luminous), остальные (5,6,7,8) — пустые разделы.

Делаю так:
ceph-disk prepare --bluestore /dev/sdc --block.db /dev/sdm6

Вот вывод:

Setting name!
partNum is 0
REALLY setting name!
The operation has completed successfully.
prepare_device: OSD will not be hot-swappable if block.db is not the same device as the osd data
prepare_device: Block.db /dev/sdm6 was not prepared with ceph-disk. Symlinking directly.
Setting name!
partNum is 1
REALLY setting name!
The operation has completed successfully.
The operation has completed successfully.
meta-data=/dev/sdc1 isize=2048 agcount=4, agsize=6400 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=0
data = bsize=4096 blocks=25600, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=1608, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
Warning: The kernel is still using the old partition table.
The new table will be used at the next reboot or after you
run partprobe(8) or kpartx(8)
The operation has completed successfully.

Ошибок нет.

Теперь делаю
ceph-disk activate-all
вот вывод:

got monmap epoch 1
2017-09-12 14:07:33.711863 7f0fba54be00 -1 bdev(0x55b99f8c6fc0 /var/lib/ceph/tmp/mnt.vyVmpd/block.db) open open got: (13) Permission denied
2017-09-12 14:07:33.711875 7f0fba54be00 -1 bluestore(/var/lib/ceph/tmp/mnt.vyVmpd) _open_db add block device(/var/lib/ceph/tmp/mnt.vyVmpd/block.db) returned: (13) Permission denied
2017-09-12 14:07:33.993025 7f0fba54be00 -1 bluestore(/var/lib/ceph/tmp/mnt.vyVmpd) mkfs failed, (13) Permission denied
2017-09-12 14:07:33.993063 7f0fba54be00 -1 OSD::mkfs: ObjectStore::mkfs failed with error (13) Permission denied
2017-09-12 14:07:33.993275 7f0fba54be00 -1 ** ERROR: error creating empty object store in /var/lib/ceph/tmp/mnt.vyVmpd: (13) Permission denied
mount_activate: Failed to activate
ceph-disk: Command '['/usr/bin/ceph-osd', '--cluster', 'ceph', '--mkfs', '-i', u'2', '--monmap', '/var/lib/ceph/tmp/mnt.vyVmpd/activate.monmap', '--osd-data', '/var/lib/ceph/tmp/mnt.vyVmpd', '--osd-uuid', u'1b0a0046-1cca-4684-93a2-8012320109d8', '--setuser', 'ceph', '--setgroup', 'ceph']' returned non-zero exit status 1
Removed symlink /etc/systemd/system/ceph-osd.target.wants/ceph-osd@1.service.
Created symlink from /etc/systemd/system/ceph-osd.target.wants/ceph-osd@1.service to /lib/systemd/system/ceph-osd@.service.
Removed symlink /etc/systemd/system/ceph-osd.target.wants/ceph-osd@0.service.
Created symlink from /etc/systemd/system/ceph-osd.target.wants/ceph-osd@0.service to /lib/systemd/system/ceph-osd@.service.
ceph-disk: Error: One or more partitions failed to activate

Что я делаю не так, товарищи?