Storage Overview
Vapor separates the management of physical storage hardware and devices from the logical storage pools assigned to virtualization workloads. This modular architecture allows administrators to provision, format, and allocate storage dynamically to virtual machines and containers without service disruptions.
Storage Architecture: Block Devices and Storage Pools
1. Host Block Devices (Physical Disks)
Physical disks represent the raw hardware storage devices connected to the host system, including NVMe SSDs, SATA HDDs, and SAS drives, as well as hardware RAID virtual drives and mapped SAN logical unit numbers (LUNs).
- Host storage devices are queried and managed via the
/storage/disksendpoints. - Administrators can perform actions such as partition table creation (GPT), disk formatting, and partition resizing directly from the web console.
2. Storage Pools (Logical Virtualization Storage)
A storage pool is a logical volume of storage managed by libvirt that holds virtual machine hard disk images (.qcow2 files) or installation media (.iso files). Vapor supports creating multiple storage pools backed by different underlying storage technologies.
- Note: Detailed configuration procedures are covered in the Virtualization Storage Pools Guide.
Supported Storage Pool Types
When provisioning a storage pool, administrators can select from several underlying directory and filesystem configurations:
- Directory (DIR) Pool: A logical folder path mapped on the host filesystem (e.g.
/var/lib/libvirt/images). Highly compatible and simple to maintain, suitable for local standalone deployments. - LVM (Logical Volume Manager): Utilizes LVM Volume Groups (VGs) and Physical Volumes (PVs) to allocate dedicated Logical Volumes (LVs) as block storage devices for VMs. Offers dynamic resizing and high performance.
- ZFS: An enterprise-grade filesystem and volume manager providing advanced features such as Copy-on-Write (CoW) snapshots, block-level compression, software RAID, and automated data integrity verification (scrubbing).
- NetFS (Network File System - NFS): Connects to remote network shares over NFS export protocols, allowing multiple VM hosts to share centralized storage.
- FS (OCFS2 Clustered Pool): Oracle Clustered File System v2 (OCFS2) mapped over iSCSI or Fibre Channel SAN devices. Facilitates concurrent active/active read-write mounts across multiple hosts, managed by the o2cb distributed locking daemon.
Storage Adapters & Multipathing
Vapor provides built-in tools to manage storage controllers and network adapters:
- Local Controllers: Built-in AHCI/SATA and NVMe controllers.
- Fibre Channel HBAs: PCIe cards enabling fiber-optic connections to enterprise SANs.
- Software iSCSI Adapters: Allows the host to connect to remote target storage portals over standard Ethernet networks. Supports initiator IQN configuration, network port binding for traffic isolation, SendTargets target discovery, and CHAP authentication sessions.
- Multipath I/O (MPIO): Maps redundant network path links (via multiple NICs or fabrics) to a single block device, preventing storage access failure if an Ethernet switch or cable fails. MPIO policies (
failoverandround_robin) can be configured at the device level.