Storage
Each node has one or more storage pools where server disks live. The agent finds volumes that could hold disks; you register them on the node’s Storage tab with Add storage. Newly enrolled nodes start with no storage.
Kinds
| Kind | Disk for each server | Notes |
|---|---|---|
| LVM thin pool | A thin volume, /dev/<vg>/<id> |
Recommended. Fast snapshots, thin provisioning. |
| LVM volume group | A thick volume, /dev/<vg>/<id> |
Overcommit is always 1 |
| ZFS dataset | A sparse zvol, /dev/zvol/<dataset>/<id> |
Snapshots visible with snapdev=visible |
| Directory (qcow2 files) | <dir>/<id>.qcow2 |
/var/lib/libvirt/images by default. Fine for a lab. |
Pool settings
| Setting | Notes |
|---|---|
| Name | Lowercase, up to 32 characters |
| Tier | NVMe, SSD or HDD. The agent detects it; ZFS and directories report SSD, so check it. Can’t change while disks are on the pool. |
| Reserved | GB kept free, up to half the capacity. The panel suggests about 2.5%. |
| Overcommit | How far thin provisioning may promise more than the capacity: 1–4. The panel suggests 1.2 for LVM thin and 1.5 for ZFS and directories. |
| Default | The first pool becomes the default |
| Enabled | Disabled pools take no new disks |
A pool shows as degraded when it’s 95% full or its volume is missing. Staff are notified.
How a disk finds a pool
Packages ask for a tier. Placement only uses nodes with an enabled pool of that tier with room under the group’s disk limit. The disk goes to the node’s default pool when its tier matches, otherwise to the matching pool with the most free space.