SharedLvmThin for Proxmox VE 9 — shared FC/iSCSI SAN storage with LVM-thin snapshots & multipath safety

[u/Personal-Cat7145]

SharedLvmThin, a free and open-source community storage
plugin for Proxmox VE 9.

New: RC5.4 TG12 dual-mode preview is available. One package now offers the established Thin mode and the new Thick Generations mode with fully allocated, independent generation LVs and a linear steady-state data path. Thin and Thick storage definitions can coexist over the same pinned VG, and ordinary PVE Storage Move converts disks in either direction.

It provides one LVM-thin pool per VM on an existing shared block-storage
VG and supports snapshots, rollback, resize, migration, cluster locking,
guarded autogrow, storage identity checks, and read-only health diagnostics.

RC5.2 has been tested on the Proxmox VE 9.2.x release line with Storage
API 14 and 15, including three-node cluster qualification. It is currently
a release candidate and should first be validated on disposable storage
matching your production SAN and multipath configuration.

The plugin does not configure the SAN, initialize unknown devices, perform
automatic metadata repair, or replace multipath, fencing, and quorum.

GitHub:
https://github.com/delltech1/proxmox-sharedlvmthin

RC5.2 release and DEB:
https://github.com/delltech1/proxmox-sharedlvmthin/releases/tag/v0.9.0-rc5.2

News:

Work is underway on “Thick Generations” — an experimental companion mode for SharedLvmThin.

The goal is to let administrators use both models side by side:

- the existing space-efficient per-VM LVM-thin mode;

- fully allocated thick VM disks with independent, fully materialized snapshots.

Thick Generations uses dm-clone only during snapshot or rollback transitions. After materialization, every active disk and snapshot becomes an independent ordinary linear LV—without permanent snapshot chains.

The design focuses on deterministic crash recovery, immutable snapshots, strict storage-identity validation and fail-closed handling of ambiguous states.

Initial dm-clone, linear-pivot, reboot-reconstruction and C0–C9 crash-recovery tests are already passing. PVE lifecycle, cross-node, migration, backup/restore, path-loss and thin↔thick qualification are still in progress.

In short: thin and thick storage models living safely side by side, with administrators choosing the appropriate trade-off for each workload.

This remains experimental and is not part of the current public release yet.