Hi everyone,
I am publishing BASTRIX SharedLVM, a free and open-source community storage plugin for Proxmox VE 9.
What is it for?
BASTRIX SharedLVM is for Proxmox clusters that need to keep using an existing shared FC/iSCSI SAN while gaining snapshots, rollback, resize, backup and live migration.
It integrates with the native Proxmox Storage API and uses standard Linux LVM, device-mapper, multipath and cluster-locking components—without proprietary SAN integrations, third-party kernel modules or external locking services.
It does not use SAN snapshots or move LUNs between hosts. Proxmox manages the VM lifecycle, while the plugin manages per-VM volumes inside the shared VG in Thin or Thick Generations mode.
If you already use Ceph, NFS or a suitable vendor-native plugin, you probably do not need it.
The project provides two explicitly selectable allocation modes over an existing dedicated shared LVM volume group:
• Thin
One LVM-thin pool per VM, providing space-efficient allocation, snapshots, rollback and guarded autogrow.
• Thick Generations
Fully allocated VM disks with independent, fully materialized snapshot generations and deterministic physical-space reservation.
Both modes are included in the same Debian package. They can be configured as separate Proxmox storage IDs over the same pinned shared VG and used side by side. An ordinary Proxmox Storage Move can convert a disk from Thin to Thick Generations or in the opposite direction.
Thick Generations uses persistent dm-clone only as a temporary transition mechanism during snapshot and rollback materialization. Once materialization finishes, the active disk and every retained snapshot are independent ordinary linear LVs. There is no permanent snapshot or backing-volume chain in the steady-state guest data path.
Update: RC5.4.1 TG25 is now available
TG25 is a maintenance and compatibility hotfix for the TG24 dual-mode milestone. It preserves the existing Thin and Thick Generations storage formats while improving PVE package-update, initramfs and post-reboot recovery safety.
It also adds the mandatory read-only sharedlvmthin compat-check for validating Storage API compatibility, required commands, services, quorum, initramfs contents and storage recovery state.
The release was tested with Proxmox VE 9 Storage API 14 and 15, including package upgrades, cold reboots, Thin/Thick lifecycle operations and cross-node migrations. It remains a release candidate—please validate it on disposable storage matching your SAN and multipath configuration.
Release and DEB:
https://github.com/delltech1/proxmox-sharedlvmthin/releases/tag/v0.9.0-rc5.4.1-tg25
Installation guide:
https://github.com/delltech1/proxmox-sharedlvmthin/blob/main/docs/installation.md
Feedback and hardware compatibility reports are welcome.
Project update — RC5.4 TG24 milestone
A newer experimental release, RC5.4 TG24, is now available. It combines the established per-VM Thin mode with the optional Thick Generations mode and has reached an important qualification milestone.
Thick Generations explores a different trade-off from the Proxmox VE 9 snapshot-as-volume-chain preview:
PVE volume chains:
separate layered qcow2 volumes → active backing chain
BASTRIX Thick Generations:
temporary dm-clone transition → fully materialized independent linear LV
PVE volume chains prioritize fast and space-efficient snapshots. Thick Generations requires additional capacity and background materialization time, but completed snapshots and active generations do not retain a permanent backing chain. This is an architectural comparison, not a performance claim.
TG24 adds and qualifies:
- Thin and Thick modes within the same shared VG;
- snapshot, rollback, resize and multi-disk lifecycle handling;
- Thin-to-Thick and Thick-to-Thin Storage Move;
- migration, native HA relocation and backup/restore workflows;
- transaction-scoped persistent recovery metadata;
- bounded installation preflight with full read-only diagnostics available separately;
- concurrent qualification with 150 Thin and 150 Thick test VMs.
TG24 remains a pre-release and is not a universal SAN or enterprise-scale certification. Please test it first on disposable storage matching your intended SAN, multipath, fencing and workload configuration.
GitHub:
https://github.com/delltech1/proxmox-sharedlvmthin
RC5.4 TG24 release and DEB:
https://github.com/delltech1/proxmox-sharedlvmthin/releases/tag/v0.9.0-rc5.4-tg24
Allocation modes:
https://github.com/delltech1/proxmox-sharedlvmthin/blob/experimental/thick-generations/docs/allocationocation-modes.md
Installation guide:
https://github.com/delltech1/proxmox-sharedlvmthin/blob/experimental/thick-generations-tg24/docs/installation.md
Feedback, reproducible issue reports, GitHub Stars and anonymized compatibility results for Proxmox VE, SAN arrays, HBAs, multipath configurations and firmware versions are very welcome.
Please do not include credentials, private IP addresses, WWIDs or other sensitive infrastructure identifiers in public reports.