Monitoring is one of those investments almost every engineering team gets right in the early days. A handful of virtual machines, a few production applications and a growing customer base make SaaS platforms an easy decision — deployment takes minutes, and dashboards are ready out of the box.
The challenge appears later, as infrastructure expands. Monitoring quietly evolves from a small operational expense into one of the largest recurring infrastructure costs, and for many organisations the first sign isn't an engineering discussion — it's a finance question: why has monitoring become one of our most expensive monthly subscriptions?
That question is pushing a growing number of UK organisations to reassess whether SaaS monitoring still represents the best long-term value, or whether a self-hosted platform built on Prometheus and Grafana would serve them better.
What Is Self-Hosted Monitoring?
Self-hosted monitoring means your organisation owns and operates the entire observability platform.
- Prometheus — collects time-series metrics via exporters.
- Grafana — turns raw metrics into beautiful dashboards.
- Alertmanager — groups related incidents and routes alerts.
- Thanos, VictoriaMetrics, or Grafana Mimir — extend retention for long-term historical data.
SaaS Monitoring vs Self-Hosted Monitoring
There's a common misconception that self-hosted is automatically superior. In reality, SaaS platforms solve genuine operational problems (easy deployment, vendor maintenance). The important question is whether your current strategy still aligns with the economics of your infrastructure today.
- SaaS Monthly Costs: Subscription-based (increases with usage).
- Self-Hosted Monthly Costs: Infrastructure-based (highly predictable).
Why Data Sovereignty Has Become a Strategic Requirement
Monitoring data is frequently underestimated. It can reveal internal IP addresses, network topology, and deployment schedules — an accurate map of your infrastructure. Keeping platforms inside a secure London Data Centre simplifies UK GDPR compliance and keeps data firmly under your control.
Why Dedicated Infrastructure Suits Self-Hosted Monitoring
Monitoring platforms continuously ingest and query large volumes of metrics. Bare Metal Servers provide the consistent CPU performance needed to support sustained ingestion without resource contention. Furthermore, utilizing high-speed NVMe Dedicated Servers ensures fast querying across long retention windows.
A Practical Migration Strategy
- Phase 1 — Mirror critical metrics into Prometheus alongside the SaaS platform.
- Phase 2 — Rebuild the most-used dashboards in Grafana.
- Phase 3 — Migrate alerting rules into Alertmanager gradually.
- Phase 4 — Introduce long-term storage (Thanos, Mimir).
- Phase 5 — Retire the SaaS platform only once proven under load.
Conclusion
Observability has evolved into a business-critical capability. For businesses operating at scale, a self-hosted observability platform provides increased flexibility, stronger data governance, and complete control over operational telemetry.
Read the original guide here: https://www.eservers.uk/blogs/self-hosted-vs-saas-monitoring/
