# Server clusters. If a server fails, the business keeps running.

Source: https://vetosec.at/en/solutions/proxmox-cluster/

If everything runs on one server, a fault stops the whole business. In a cluster another server takes over automatically. We build Proxmox clusters and replace VMware along the way.

- **Highly available** from 3 servers
- **No** VMware licences
- **Migration** with rollback plan

## What changes for you

- **Keep working when a server fails**: Virtual machines restart automatically on the remaining servers. At most your team notices a short interruption.
- **Updates during working hours**: Running machines move to another server before an update. Weekend maintenance windows become rare.
- **No more VMware licences**: Since the Broadcom takeover VMware licences have become much more expensive for many businesses. Proxmox needs no licence; optional vendor support costs a fraction.
- **A snapshot before every change**: A snapshot before every change. If something goes wrong, the old state is back in seconds.

## What runs behind it

- **Separate networks**: Separate networks for cluster, storage and management. A fault in one does not take down the others.
- [**Mirrored storage**](https://vetosec.at/en/solutions/fileserver/): Checksummed storage with replication between servers.
- [**Backup included**](https://vetosec.at/en/solutions/backup/): Backup of every machine, encrypted offsite, restores tested.
- [**Admin access only with MFA**](https://vetosec.at/en/solutions/single-sign-on/): The admin console is unreachable from the internet, sign-in via single sign-on.

[How we build in general](https://vetosec.at/en/how-we-build/)

## What it looks like

- Cluster: Several servers in one cluster, ZFS storage, virtual machines and containers spread across nodes. Managed from one interface, reachable only from the management zone.

## Proof of Concept

**Try Proxmox before you switch.**

We move a few of your virtual machines into a test cluster. You see performance, management and failover on your own systems.

Request a PoC

## Service or project

**We run it for you, or your team takes over.**

As a managed service for a fixed monthly price, with updates, backup and monitoring. Or as a project with handover of network plan, runbook and all credentials.

## For IT leads

Technical details: Proxmox VE · KVM · ZFS · Proxmox Backup Server

- **Virtualisation**: Proxmox VE on Debian with KVM and LXC, vendor subscription recommended for production.
- **High availability**: From three nodes, or two nodes plus a quorum device. Machines restart automatically on failure.
- **Storage**: ZFS with checksums and replication between nodes.
- **Networks**: Separate networks for cluster traffic, storage and management.
- **Maintenance**: Live migration before updates, a snapshot before every change.
- **Management**: Reachable only from the internal network, sign-in via single sign-on with MFA.
- **Migration**: From VMware ESXi or Hyper-V machine by machine, with a rollback plan.

## Further reading

More on the topic

- [**VMware alternative**](https://vetosec.at/en/it-security/vmware-alternative/): Since Broadcom acquired VMware, many companies are looking for an alternative virtualisation platform.
- [**RTO and RPO**](https://vetosec.at/en/it-security/disaster-recovery/): RTO and RPO are the two numbers that make recovery plannable.
- [**Warum unsere Infrastruktur anders aufgebaut ist**](https://vetosec.at/en/articles/cybersecurity/vetosec-infrastruktur-aufbau/): Bestmöglich und bezahlbar statt billig oder überdimensioniert: Die Bauprinzipien hinter vetosec-Systemen, offen erklärt.

## Frequently asked questions

### Is Proxmox ready for production?

Yes. Proxmox VE is developed by a Vienna-based company, built on Debian, KVM and LXC and has run in companies and data centres for years. For production we recommend the vendor subscription.

### How many servers does a cluster need?

At least three for real high availability. Two servers work with an extra small quorum device.

### How does migrating from VMware work?

Machine by machine. Each one is tested, cutover happens outside working hours, and the way back stays open until the end.

### Who do you offer this to?

For regulated companies, professions bound by confidentiality and anyone processing sensitive data, and for companies of about 30+ staff with critical systems.

## Related

- [Solutions](https://vetosec.at/en/solutions/): Nextcloud, SSO, backup, clusters
- [Managed services](https://vetosec.at/en/services/managed-services/): fixed price per service
- [How we build](https://vetosec.at/en/how-we-build/): security and backup standards

## Proxmox VE clusters, VMware migration and support in Austria

vetosec builds and runs Proxmox VE clusters across Austria and migrates VMware ESXi or Hyper-V environments VM by VM.

Updated: October 19, 2026

Provider: vetosec, Dipl.-Ing. Samuel Ziegler, BSc, Berndorf, Lower Austria, Austria. Contact: https://vetosec.at/en/contact/