Replication of a VM between two independent Proxmox clusters (LVM storage)

[katti]

Hello,

I am facing a design question regarding VM replication between two independent Proxmox clusters.

Environment

• Two separate Proxmox clusters (Cluster A and Cluster B)
• No shared cluster configuration
• Both clusters use LVM storage (no ZFS)
• Inter-site VPN link
• Proxmox Backup Server available

Requirement

The objective is to ensure activity continuity by having a VM from Cluster A available on Cluster B with minimal delay.
The two clusters are fully independent, and storage is LVM on both sides.
I would like to understand what is the correct and supported way to replicate (or keep synchronized) a VM from one cluster to another in this context.
Are there any recommended approaches or technical constraints to be aware of when both sides use LVM?


Thank you for your guidance.

 

[bbgeek17]

Hi @katti , currently there is no PVE mechanism that would synchronously or asynchronously replicate your volumes between the site when LVM is involved.
You either need to move replication down the stack (into the underlying storage /SAN) or up the stack (special sync application or application layer sync).

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Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[Onslow]

@katti
Depending on your requirements on a how long the services can be unavailable and on how much fresh data can be lost, a workaround could be frequent backups to PBS. And restoring to the other cluster when needed).

Thanks to "dirty bitmaps" ( https://pbs.proxmox.com/docs/technical-overview.html#fixed-sized-chunks ), backups don't necessarily take much time. (Note that dirty bitmaps are reset if the VM was rebooted after the previous backup).