High Availability & Clustering
Failover clusters and replication so one failure does not stop the business.
- Covers
- Failover clusteringStorage replicationRedundant networkingSQL Always OnFailover testing
- Patterns
- Cold standby · Active-passive cluster · Active-active · Stretched / two-site
- How we work
- Define → Design → Build → Prove → Maintain
Clustered servers still share a single storage unit that can fail. Our fix: Replicated or redundant storage paths.
See the common problemsThe cluster was built years ago and nobody has tried a failover since. Our fix: Scheduled failover tests with written results.
See the common problemsEvery redundant server connects through the same single switch. Our fix: Dual switching and teamed network links.
See the common problemsPick an availability target to see how much downtime it permits, and the design it usually takes.
Try the uptime target calculatorAnswer a few quick questions and a Skylius specialist will prepare practical recommendations.
Request a consultationWhen one server stops, the business should not.
We design high-availability for the systems you cannot afford to lose: failover clusters, replicated storage, redundant networking and power, then prove it works with planned failover tests.
Hidden single points of failure
Redundancy that exists only on paper.
Two servers, one storage box
Clustered servers still share a single storage unit that can fail.
Untested failover
The cluster was built years ago and nobody has tried a failover since.
One switch in the middle
Every redundant server connects through the same single switch.
Maintenance means downtime
Updates are postponed for months because rebooting stops the business.
What we deliver
Availability designed layer by layer.
Agreed uptime and recovery goals for each critical system.
Windows Failover Cluster, vSphere HA, Proxmox HA or application-level options.
Shared, replicated or hyper-converged storage with no single point of failure.
Dual switches, teamed links, dual PSUs on separate UPS feeds.
SQL Server Always On, load-balanced web tiers and similar patterns.
Planned tests with a report and an updated runbook.
Patterns
Match the design to the uptime you need.
Cold standby
A spare or replicated server brought online manually.
Active-passive cluster
A second node takes over automatically if the first fails.
Active-active
Load is shared, so losing a node only reduces capacity.
Stretched / two-site
Nodes split across two rooms or sites for wider protection.
Interactive · uptime target calculator
What does your uptime target really allow?
Pick an availability target to see how much downtime it permits, and the design it usually takes.
What your target means
Indicative only. Figures are arithmetic from your target. The right design also depends on recovery time, data loss tolerance and budget.
Send this on WhatsAppHow we work
A clear process, no surprises.
Define
Critical systems and uptime goals agreed.
Design
Cluster, storage, network and power layout.
Build
Nodes, storage and networking configured.
Prove
Controlled failover tests with results.
Maintain
Rolling updates and periodic re-tests.
Platforms we work with
Proven platforms, chosen per project.
FAQ
Questions about High Availability & Clustering.
Have a different question? A specialist will reply on WhatsApp.
No. A two-node cluster or a replicated standby server is within reach of many mid-sized businesses, and it is often cheaper than a single long outage.
High availability keeps systems running through a hardware failure. Backup lets you recover data after deletion, corruption or ransomware. You need both, and they solve different problems.
With shared or synchronously replicated storage, typically nothing committed is lost. With asynchronous replication there may be a small window, which we agree with you in advance.
At least once or twice a year, and after major changes. We schedule tests out of hours and give you a short report each time.
Possibly. Cluster nodes should be matched in hardware and firmware, so we check compatibility first.
Some editions and features do, depending on the platform and application. We list exactly what is needed in the design.
We look at the whole chain: dual power supplies on separate UPS feeds, dual switches and teamed links, so the cluster is not undone by one cable.
Yes. Stretched clusters or replication between two rooms or sites protect against a local fire, flood or power issue.
The server lifecycle
Plan, build, run, protect, scale.
Every service in this section, organised by the stage of your server journey.
High Availability & Clustering
Let's remove the single points your business depends on.
Tell us about your servers and goals. We will review them and send a clear, itemised proposal.
