High Availability – Availability as a principle

High availability, durchdacht

From redundant data centres to clusters and replication, right through to failover within seconds: this is how centron keeps your services up and running.

The HA modules

Availability is built up in layers

True high availability is not a single product, but rather the interplay between infrastructure, architecture and processes.

Redundant infrastructure

UPS, emergency power systems, separate fire compartments and multiple redundant power connections – the physical infrastructure at our data centre in Hallstadt near Bamberg.

Highly available architecture

Managed clusters with load balancing, real-time replication and automatic failover keep applications online – even if individual components fail.

Contingency planning

cProtect replicates data every 15 minutes to a separate fire compartment within the Hallstadt data centre – with immutable data states and failover within seconds, even in the event of a ransomware attack.

Vigilant processes

24/7 monitoring with alerts and – in the case of managed services – proactive fault resolution by centron experts before users even notice anything is wrong.

Contractual undertakings

Availability, in black and white

These values are laid down in the service specifications and apply per calendar month. cProtect has no availability commitment of its own; the service follows the SLA of the infrastructure on which the failover system runs. For a highly available system, the High Availability Pool is therefore the foundation.

SLAs & key figures
ServiceValueScope
ccloud³ VMs in the High Availability Pool99.8 %per month · ccloud³ service specification
ccloud³ VMs in the Worker and Power Pool99.5 %per month · ccloud³ service specification
Managed Server99.5 % / 99.8 %Worker/Power Pool or HA Pool
Volumes and S3 Object Storage99.9 %per month · service specification
Colocation network99.9 %per month · Colocation service specification
cProtect replication intervalapprox. 15 minutescProtect service specification
Customised SLAsby arrangementManaged Cluster and Full Managing
From Need to Architecture

How much uptime does your system require?

Not every application requires geographical redundancy – but every one requires a well-thought-out plan. During the high-availability consultation, we analyse the costs of downtime, define RPO and RTO targets, and design the appropriate architecture: from a pair of load balancers to cross-site replication.

99.8 %High Availability Pool · guaranteed per month in the service specification
Find out more about cProtect
  • Needs analysis – Clarify downtime costs and objectives
  • Definition of RPO/RTO as a basis for architecture
  • A tailor-made solution From clusters to geographical redundancy
  • Contractual SLAs to give you certainty in your planning
High Availability FAQ

Frequently asked questions about high availability

What do 99.5 %, 99.8 % and 99.9 % availability actually mean?

The SLAs apply per month. With around 730 hours in a month, 99.5 % corresponds to up to about 3.7 hours of downtime, 99.8 % to up to about 1.5 hours and 99.9 % to up to about 44 minutes. For highly available systems, the High Availability Pool with 99.8 % is therefore the right foundation. Volumes, Object Storage and the colocation network are at 99.9 %.

Is a backup not enough?

Backups protect data, not availability. Restoring large systems takes hours. High availability starts earlier, with redundant systems and failover, so that operations do not come to a standstill in the first place. Backups remain mandatory nonetheless.

How do I achieve high availability for my application?

Typically with a Managed Cluster: several nodes in the High Availability Pool, load balancing, replication and automatic failover. centron plans and operates this and backs it with customised SLAs.

What happens if the production system fails?

With cProtect, a copy of your system that is at most around 15 minutes old is kept ready in a separate fire compartment of the Hallstadt data centre. In the event of a failure, the failover system is activated and takes over operation. cProtect has no availability SLA of its own; the SLA of the infrastructure on which the failover system runs applies.
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