LXD overreports LVM thin-pool storage usage in /1.0/storage-pools/<pool>/resources and `lxc storage info`

[Maharacha]

Please confirm

• I have searched existing issues to check if an issue already exists for the bug I encountered.

Distribution

Ubuntu server

Distribution version

22.04.5

Output of snap list --all lxd core20 core22 core24 snapd

Name    Version         Rev    Tracking       Publisher   Notes
core20  20260105        2717   latest/stable  canonical✓  base,disabled
core20  20260211        2769   latest/stable  canonical✓  base
core22  20260128        2339   latest/stable  canonical✓  base,disabled
core22  20260225        2411   latest/stable  canonical✓  base
core24  20260317        1587   latest/stable  canonical✓  base
lxd     5.21.4-8a3cf61  36579  5.21/stable    canonical✓  disabled,held
lxd     5.21.4-9eb1368  36971  5.21/stable    canonical✓  held
snapd   2.73            25935  latest/stable  canonical✓  snapd,disabled
snapd   2.74.1          26382  latest/stable  canonical✓  snapd

System info

kernel_version: 6.8.0-90-generic
lxc version: 5.21.4 LTS
lxd version: 5.21.4 LTS
storage backend: lvm

Instance log

n/a

Expected behavior

lxc storage info <pool> show correct space used.
/1.0/storage-pools/<pool>/resources endpoint show correct space used.

Actual behavior

In thinPoolVolumeUsage() LXD reads lv_size,data_percent,metadata_percent and computes:

usedSize = totalSize * ((dataPerc + metaPerc) / 100)

This is incorrect because metadata_percent is relative to the thin-pool metadata LV, not to the thin-pool data LV / total pool size. Adding the percentages and applying them to totalSize overcounts usage, often by a very large amount.

Example:

• thin pool size: 7681263796224 bytes
• data_percent: 41.09
• metadata_percent: 28.30
• LXD reports used: 5330028948199 bytes (4.85 TiB)

But actual data allocation is about 3156231293868 bytes (2.87 TiB), and metadata usage is only ~33 MiB because the metadata LV itself is 112 MiB.

This affects:

• GET /1.0/storage-pools//resources
• lxc storage info <pool>

Steps to reproduce

Run lxc storage info <pool>.
Compare what is actually used.
Compare with lvs <VG>.

Information to attach

• Any relevant kernel output (dmesg)
• Instance configuration (lxc config show <instance> --expanded)
• Main daemon log (at /var/log/lxd/lxd.log or /var/snap/lxd/common/lxd/logs/lxd.log)
• If a lxc command fails, output of the command with --debug
• Output of the daemon with --debug (or use lxc monitor while reproducing the issue)