====== Move DB to new drive ======

<code bash>
blkid
/dev/nvme0n1p3: PARTLABEL="DB" PARTUUID="b30d904f-94ce-4776-982a-db5947dac1cd"

ceph osd set noout
systemctl stop ceph-osd@3
systemctl disable ceph-osd@3

ddrescue -f -n -vv c66f0c74-12b2-aa42-afc4-f4bd12bfa87c DB.img<NEW>
</code>

Replace disk, restore partition layout.

<code bash>
ddrescue -f -n -vv DB.img /dev/nvme0n1p3
</code>

Restore original UUID
<code bash>
gpart /dev/nvme0n1
x
c
3
<UUID>
w
</code>

<code bash>
partprobe
</code>

Verify ceph osd config:
<code bash>
ceph-volume lvm list
</code>

Activate volume:
<code bash>
ceph-volume lvm activate --all
</code>

===== LVM way =====

Idea is to:
  * add 2nd disc to the same LVM PV,
  * then force LV data movement to second storage,
  * remove 1st disc from LVM PV

<code bash>
pvcreate /dev/sdd7
vgextend ceph-bf4ade97-581a-4832-a517-2d83503fe01d /dev/sdd7

lvscan
pvmove -n /dev/ceph-bf4ade97-581a-4832-a517-2d83503fe01d/osd-db-40769e33-2fb8-431d-8996-40870e35c3ee /dev/sdc7 /dev/sdd7

vgreduce ceph-bf4ade97-581a-4832-a517-2d83503fe01d /dev/sdc7
pvremove /dev/sdc7
</code>

Activate volume:
<code bash>
ceph-volume lvm list

  [db]          /dev/ceph-bf4ade97-581a-4832-a517-2d83503fe01d/osd-db-40769e33-2fb8-431d-8996-40870e35c3ee

      block device              /dev/ceph-feea9396-abeb-4b50-8cdc-3a35598ec651/osd-block-c794c0d0-0515-4bfb-bb54-00656fa8712d
      db device                 /dev/ceph-bf4ade97-581a-4832-a517-2d83503fe01d/osd-db-40769e33-2fb8-431d-8996-40870e35c3ee
      db uuid                   5zRs08-Hif1-hIFp-rNfO-WTah-26MG-ojnLVh
      devices                   /dev/sdd7

ceph-volume lvm activate --all
</code>


====== DRAFTS: ======

<code>
zfs create -V 5GB rpool/data/DB

ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-3 --devs-source /var/lib/ceph/osd/ceph-3/block.db --command bluefs-bdev-migrate --dev-target /dev/zvol/rpool/data/DB

inferring bluefs devices from bluestore path
 device removed:1 /var/lib/ceph/osd/ceph-3/block.db
 device added: 1 /dev/zd144
</code>

Rollback:
<code bash>
ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-3 --devs-source /var/lib/ceph/osd/ceph-3/block.db --command bluefs-bdev-migrate --dev-target /dev/nvme0n1p3
</code>

/usr/bin/ln -snf /dev/zd144 /var/lib/ceph/osd/ceph-3/block.db



ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-12 --devs-source /var/lib/ceph/osd/ceph-12/block --devs-source /var/lib/ceph/osd/ceph-12/block.db --command bluefs-bdev-migrate --dev-target --dev-target /dev/vdg1