High availability cluster

Your services stay up when a server goes down

We build HA clusters on Proxmox VE, Hyper-V, SUSE Virtualization, and XCP-ng that detect node failures and restart your virtual machines automatically.

Automatic failover and failback
Continuous VM replication
Distributed storage with Ceph
Failure detection in seconds
Node health monitoring and alerting

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No single point of failure

Verified
failover

Minutes
to recover

Node loss
resilient

What an HA cluster gives you

A high availability cluster keeps services running through hardware failures, maintenance windows, and even regional outages. Here is what that means in practice.

Workloads that justify an HA cluster

Databases and message queues
E-commerce and payment systems
SaaS platforms and client portals
ERP, CRM, and business-critical applications

Healthcare and regulated systems
Streaming and real-time services
File and storage services
VoIP and communication platforms

Turnkey HA cluster – from design to
verified failover

The service does not end when the cluster is installed – it ends when failover has been demonstrated on your actual workloads.

Turnkey HA cluster – from design to<br>verified failover

1
Assessment and design

We identify your critical applications, acceptable downtime, and recovery targets. We audit the existing hardware, network, and storage. Based on that, we design the cluster – node count, storage layout, and failover logic – to meet those targets.
2
Node and network setup

We configure the servers as cluster nodes with redundant interconnects. Failover IPs and network redundancy are set up and verified. Shared or distributed storage is deployed for data redundancy.
3
Cluster configuration

We install and configure cluster services on Proxmox VE, Microsoft Hyper-V, SUSE Virtualization, or XCP-ng. Cluster resources – virtual IPs, storage, and compute – are defined and prioritized. Automatic failover and failback rules are configured per workload.
4
Failover testing

We simulate node failures and verify that virtual machines restart where they should, within the agreed time. Performance under failover load is measured, not assumed. Recovery from storage and network failure scenarios is tested as well.
5
Monitoring and maintenance

Monitoring tracks node health, replication status, and cluster quorum. Alerts fire on critical events – node loss, degraded replication, resource exhaustion. Scheduled maintenance keeps the cluster stable without interrupting services.
6
Ongoing support

Our engineers remain available for troubleshooting and configuration changes. We apply updates and upgrades node by node, with no cluster downtime.

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FAQ

How fast does failover actually happen?

For most HA setups, a virtual machine from a failed node restarts on a healthy one within one to five minutes – the exact time depends on the platform, storage, and how quickly the guest OS boots. For planned events, live migration moves VMs with no interruption at all. If even a minute is too long, see the fault tolerance question below.
How many servers do I need for an HA cluster?

Three nodes is the practical minimum – a cluster needs a majority vote (quorum) to decide which nodes are healthy and avoid split-brain situations. A two-node setup is possible with an external quorum device, but three or more nodes is the configuration we recommend.
Do all four hypervisors support high availability?

Yes. Proxmox VE has a built-in HA manager, Microsoft Hyper-V uses Windows Server failover clustering, SUSE Virtualization ships with HA out of the box, and XCP-ng provides it through its management stack. The principles are the same – the tooling differs, and we match it to your team.
What storage does an HA cluster require?

Failover only works if every node can reach the VM data, so the cluster needs shared or distributed storage – for example Ceph, replicated volumes, or an external storage system. Purely local disks are not enough; we design the storage layer together with the cluster.
Does an HA cluster protect me against data loss?

HA protects availability, not history – if data is corrupted or deleted, replication faithfully copies the damage to every node. That is why backups remain mandatory alongside any cluster. How much recent data a failover can lose depends on whether replication is synchronous or asynchronous, and we set that according to your recovery point objective.
Will users notice anything during a failover?

For planned events – maintenance, load rebalancing – virtual machines move between nodes live, and users notice nothing. For an unplanned node failure, affected VMs restart on another node, so active sessions on those VMs are briefly interrupted and then resume. Well-designed applications reconnect automatically, and for most users it looks like a page reload.
What is the difference between high availability and fault tolerance?

High availability restarts affected VMs on another node – there is a brief interruption. Fault tolerance keeps a live mirror of the running machine, so a node failure causes no interruption at all – at the cost of roughly double the resources. Most workloads are well served by HA; fault tolerance is reserved for the few that cannot tolerate even seconds of downtime.
Do my applications need changes to run in an HA cluster?

Usually not – VM-level HA is transparent to the applications inside. For databases and other stateful services, application-level replication can be added on top of cluster HA for even tighter recovery guarantees, but it is an option, not a requirement.