Ceph » RADOS

I created an OSD on top of a logical volume with a VDO device underneath.

Ceph is unaware of how much compression and deduplication has been done.

[root@reesi003 ~]# ceph osd df | grep 'ID\|^55'
ID CLASS WEIGHT  REWEIGHT SIZE  USE    AVAIL  %USE  VAR  PGS 
55   hdd 3.65810  1.00000 3745G 55080M  3692G  1.44 0.06 367 

[root@reesi004 ~]# vdostats --hu
Device                    Size      Used Available Use% Space saving%
/dev/mapper/vdo_sda       3.6T     25.1G      3.6T   0%           21%

Note the space saving percentage is incorrect. I filed https://bugzilla.redhat.com/show_bug.cgi?id=1563794 for that.

Steps to reproduce:

vdo create --name vdo_sda --device=/dev/sda --writePolicy=async

pvcreate /dev/mapper/vdo_sda

vgcreate vg_sda /dev/mapper/vdo_sda

lvcreate -l 100%FREE -n lv_sda vg_sda

ceph-volume lvm create --bluestore --data vg_sda/lv_sda --block.db journals/sda