Technical reference

Glossary infrastructure & virtualisation

Definitions of the technical terms used in VMware Exit projects, from VMware infrastructure to Proxmox VE operations.

Backup

PBS: Proxmox Backup Server. Backup solution for Proxmox VMs and containers, with deduplication, compression, verification and restore capabilities. Its scope is narrower than a heterogeneous data-protection platform such as Veeam.

Cluster

Corosync: Communication and quorum engine used by a Proxmox VE cluster. It synchronises cluster state and contributes to node failure detection.
Pacemaker: Linux cluster resource manager often paired with Corosync. Proxmox VE does not use Pacemaker for HA; it provides its own CRM and LRM services.

Container

LXC: Linux Containers. Lightweight containerisation technology built into Proxmox VE. Less isolated than a VM, LXC shares the host kernel and consumes fewer resources.

Hypervisor

ESXi: VMware (now Broadcom) type-1 hypervisor. Proprietary kernel optimised for virtualisation, replaced in open-source contexts by KVM/Proxmox.
KVM: Kernel-based Virtual Machine. Linux kernel module that turns Linux into a type-1 (bare-metal) hypervisor. Technological base of Proxmox VE, direct competitor to VMware ESXi.
Proxmox VE: Open-source virtualisation platform based on KVM and LXC. Proxmox Virtual Environment includes a web UI, HA cluster management, VM replication and native integration with Ceph and PBS.

Migration

OVF / OVA: Open Virtualization Format. Standard VM packaging format portable between hypervisors. OVA = OVF archive + disks. Proxmox can import OVAs exported from VMware.
V2V: Virtual-to-Virtual. Conversion of a VM from one format/hypervisor to another. Common tools: virt-v2v (Red Hat), OVA import, or manual conversion via virsh/qemu-img.

Network

SDN: Software-Defined Networking. In Proxmox VE, the SDN module manages zones, VNets, VXLAN and EVPN. It covers part of a target network design but is not a complete replacement for NSX.
VXLAN: Virtual Extensible LAN. Network encapsulation protocol (RFC 7348) for creating L2 overlay networks over L3 infrastructure. Used by NSX and Proxmox SDN.

Operations

Snapshot: Point-in-time VM state capture. Used for incremental backups (PBS) and pre-migration restore points. Proxmox supports RAM snapshots (with memory state) and disk-only snapshots.

Performance

IOPS: Input/Output Operations Per Second. Storage throughput metric that must be read with latency, block size, queue depth and read/write ratio. A standalone IOPS figure is not enough to size a target.

Resilience

DRP: Disaster Recovery Plan. Set of procedures for restoring a system after a disaster. Different from HA (real-time): DRP targets a contractually defined RTO/RPO.
HA (High Availability): Recovery mechanism that restarts a VM on a healthy node after a host failure. Proxmox VE uses Corosync for the cluster and its own HA CRM/LRM services to orchestrate resources.
RPO: Recovery Point Objective. Maximum acceptable data loss, expressed in time. Defines the minimum backup frequency.
RTO: Recovery Time Objective. Maximum acceptable downtime duration. Key DRP indicator: defines the time between failure and activity resumption.

Storage

Ceph: Open-source distributed storage system. Provides block (RBD), object (S3-compatible) and file (CephFS) storage. Native integration in Proxmox VE for shared storage without SAN.
Ceph RBD: RADOS Block Device. Ceph block interface used by Proxmox to store VM disks. Supports snapshots, clones and thin provisioning.
DRBD: Distributed Replicated Block Device. Block replication technology between Linux nodes, historically used to build redundant storage. Integration and support must be checked for the selected solution, such as LINSTOR.
NFS: Network File System. Network file-sharing protocol supported by Proxmox as shared storage. Performance depends on the server, network, protocol and I/O profile and should be measured against the target workloads.
SAN: Storage Area Network. Dedicated storage network (FC, iSCSI, NVMe-oF). Proxmox supports iSCSI and FC via LVM storage plugins. Replaceable by Ceph to reduce proprietary hardware dependency.
Thin provisioning: Dynamic storage allocation. A thin-provisioned 100 GB disk only occupies the space actually used. Proxmox, Ceph and ZFS natively support thin provisioning.
ZFS: Advanced filesystem and volume manager. Natively integrated into Proxmox VE: handles snapshots, checksums, compression and software RAID (RAIDZ). Local alternative to Ceph for small clusters.

VMware

DRS: Distributed Resource Scheduler. vSphere mechanism for VM placement and load balancing. Proxmox VE provides Cluster Resource Scheduling (CRS) for HA resources, but its scope and operational maturity are not identical to DRS.
NSX: VMware network and security platform covering microsegmentation, overlays and distributed routing. Proxmox SDN addresses some network use cases but does not replace the full NSX feature set on its own.
Storage vMotion: Live storage migration of a VM between VMware datastores. Proxmox VE can move a disk to another storage while the VM is running, subject to the capabilities of the source and target storage.
vCenter: Central VMware management platform. Orchestrates vSphere clusters, vMotion, DRS and HA. Sold separately by Broadcom since the 2023 VMware acquisition.
vMotion: Live VM migration between ESXi hosts. Proxmox VE provides online migration through KVM/QEMU; shared storage makes it faster, while some local-storage cases require disk transfer.
vSAN: VMware hyperconverged storage solution that creates a distributed datastore from local ESXi host disks. Ceph RBD can play a similar role on Proxmox, with a different architecture and operating model.
vSphere: VMware virtualisation suite comprising ESXi and vCenter. De facto enterprise standard until the Broadcom acquisition and pricing restructure.

Vendor

Broadcom: Semiconductor company that acquired VMware in late 2023 for $61 billion. Restructured VMware pricing from a per-CPU to a per-core model, with significant increases for mid-market enterprises.

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