LXD reporting different pool capacity from Ceph

LXD
1

I have noticed that under lxc storage info, the reported capacity of the pool differs from ceph df:

$ lxc storage info remote
info:
  description: ""
  driver: ceph
  name: remote
  space used: 176.58GB
  total space: 8.10TB
used by:
  images:
  - 46701fa2d99c72583f858c50a25f9f965f06a266b997be7a57a8e66c72b5175b
  - 961fe898000818bd2d8262ba9cb5037defe8c08cce5f85246e97429c2f927a2f
  instances:
  - container
  - vm
  profiles:
  - default
  - vm

$ ceph df
--- RAW STORAGE ---
CLASS  SIZE     AVAIL    USED     RAW USED  %RAW USED
hdd     22 TiB   21 TiB  130 GiB   138 GiB       0.63
ssd    346 GiB  310 GiB   36 GiB    37 GiB      10.57
TOTAL   22 TiB   22 TiB  166 GiB   175 GiB       0.78
 
--- POOLS ---
POOL                   ID  PGS  STORED   OBJECTS  USED     %USED  MAX AVAIL
device_health_metrics   1    1      0 B        9      0 B      0    6.2 TiB
lxd-storage             2  256   64 GiB   18.48k  164 GiB   0.86    7.2 TiB
cephfs_metadata         3   32  2.6 MiB       23  8.0 MiB      0    7.1 TiB

The pool I used in this case was lxd-storage. My question is how does LXD fetch the capacity of a Ceph storage pool given that the values differ by nearly a full TB?

2

Used: 176GB is 164GiB
Total: 8100GB is 7543GiB, LXD reports total space, not available space which should explain the difference

3

Oh right, didn’t notice the units of measurement for some reason. Thank you.