Storage Architecture & Pools

PiVirt provides a unified storage abstraction layer supporting multiple backends: local directory filesystems, LVM thin provisioning, network iSCSI block storage, NFS shares, and clustered OCFS2 volumes.

Storage Architecture

flowchart TB
    subgraph DiskLayer["VM Disk Layer"]
        LCL["Local (qcow2/raw)"]
        ISC["iSCSI (block)"]
        NFS_D["NFS (file)"]
    end

    subgraph PoolMgr["Storage Pool Manager"]
        LVM_P["LVM Pool"]
        ISC_P["iSCSI Pool"]
        NFS_P["NFS Pool"]
    end

    LCL --> LVM_P
    ISC --> ISC_P
    NFS_D --> NFS_P

Storage Pools

Local Directory Pool

storage:
  pools:
    - name: "default"
      type: "dir"
      path: "/var/lib/pivirtd/images"

LVM Thin Pool

storage:
  pools:
    - name: "lvm-pool"
      type: "lvm"
      volume_group: "pivirtd-vg"
      thin_pool: "pivirtd-thin"

iSCSI Pool

storage:
  pools:
    - name: "iscsi-pool"
      type: "iscsi"
      target_iqn: "iqn.2024-01.hu.pilab:storage"
      portal: "10.0.1.10:3260"

NFS Pool

storage:
  pools:
    - name: "nfs-pool"
      type: "nfs"
      server: "nas.pilab.hu"
      export: "/exports/pivirtd"
      version: "4.2"

Volume Types

Raw Volumes

Direct block device access
Best performance
No snapshots (unless backend supports)

QCOW2 Volumes

Copy-on-write
Snapshots and cloning
Compression and encryption

Thin Provisioning

Allocate on demand
Over-provisioning support
Space reclamation with discard

Volume Operations

Create Volume

pvcli storage volume create \
  --pool default \
  --name data-01 \
  --size 100Gi \
  --format qcow2

Clone Volume

pvcli storage volume clone \
  --source data-01 \
  --name data-01-clone

Snapshot

pvcli storage snapshot create \
  --volume data-01 \
  --name backup-01

Resize

pvcli storage volume resize \
  --name data-01 \
  --size 200Gi

Cluster Storage (OCFS2)

For multi-node clusters, PiVirt uses OCFS2 for shared block storage:

cluster:
  name: "pivirt-cluster"
  o2cb:
    stack: "o2cb"
    nodes:
      - name: "node-01"
        ip: "10.0.1.10"
      - name: "node-02"
        ip: "10.0.1.11"
  fencing:
    enabled: true
    agent: "ipmi"