How does VM replication work in Proxmox VE with ZFS, and how can it be configured for high availability?

To use replication, several prerequisites must be met. At least two nodes must be part of the same cluster. The VM disks must reside on local ZFS storage. Both source and target nodes must have ZFS pools with identical names, and the target node must have sufficient storage capacity .

Proxmox uses ZFS snapshot technology to implement replication. During the initial synchronization, a full copy of the VM disk is transmitted. Subsequent replications transfer only incremental changes, significantly reducing network traffic . The pvesr command-line tool manages replication tasks, allowing administrators to define schedules and targets.

To configure replication:

1. Create matching ZFS storage pools on all cluster nodes. 2. Ensure storage names are identical across nodes. 3. Select the VM, navigate to the Replication tab, and add a replication job specifying the target node and interval . 4. Monitor replication status via the Replication tab logs.

Replication can also be combined with High Availability settings. If a node fails, HA can automatically restart the VM on the replicated node .

While replication improves redundancy and reduces migration time, it does not replace backups. Replication mirrors changes, including corruption or accidental deletion. A separate backup strategy remains essential for full data protection.