High Availability Architectures and Best Practices

Evidian SafeKit

What are the high availability architectures and the best practices?


This article explores the different high availability architectures and the best practices by given the pros and cons of each architecture.

High availability architectures and best practices

The following comparative tables explain in detail the SafeKit high availability architecture and its best practices (SafeKit is a software high availability product).

What are the high availability architectures?

There are two types of high availability architectures: those for backend applications such as databases and those for frontend applications such as web services.

High availability architectures for backend are based on 2 servers sharing or replicating data with an automatic application failover in the event of hardware of software failures.

High availability architectures for frontend are based on a farm of servers (2 servers or more). The load balancing is made by hardware or software and distributes the TCP sessions to the available servers in the farm.

Moreover, you have to choose between high availability at the application level or at the virtual machine level.

Comparative tables on high availability architectures and best practices

Pros and cons of high availability architectures

Software clustering vs hardware clustering More info >

A software cluster with SafeKit installed on two servers Hardware clustering with external shared storage

Shared nothing vs a shared disk cluster More info >

SafeKit shared-nothing cluster: easy to deploy even in remote sites Shared disk cluster: complex to deploy

Application High Availability vs Full Virtual Machine High Availability More info >

High availability at application level High availability at virtual machine level

High availability vs fault tolerance More info >

SafeKit high availability vs fault-tolerance Fault tolerance system

Synchronous replication vs asynchronous replication More info >

SafeKit synchronous replication with no data in case of failure Asynchronous replication with data loss on failure

Byte-level file replication vs block-level disk replication More info >

Byte-level file replication between two servers Block-level disk replication between two servers

Heartbeat, failover and quorum to avoid 2 master nodes More info >

Simple quorum in a SafeKit cluster with a split brain checker configured on a router Complex quorum in other clusters: third machine, special quorum disk, remote hardware reset

Virtual IP address primary/secondary, network load balancing, failover More info >

No special network configuration in a SafeKit cluster Special network configuration in other clusters

SafeKit: an ideal solution for a partner application

This platform agnostic solution is ideal for a partner with a critical application and who wants to provide a redundancy and high availability option easy to deploy to many customers.

This clustering solution is also recognized as the simplest to implement by our partners.

SafeKit Modules for Plug&Play Redundancy and High Availability Solutions

SafeKit Modules for Plug&Play High Availability Solutions

Network load balancing and failover

Windows farm

Linux farm

Generic Windows farm   > Generic Linux farm   >
Microsoft IIS   > -
Apache   >
Amazon AWS farm   >
Microsoft Azure farm   >
Google GCP farm   >
Other cloud   >

Advanced clustering architectures

Several modules can be deployed on the same cluster. Thus, advanced clustering architectures can be implemented:

Demonstrations of Redundancy and High Availability Solutions

SafeKit Webinar

This webinar presents in 2 minutes Evidian SafeKit.

In this webinar, you will understand SafeKit mirror and farm clusters.

Microsoft SQL Server Cluster

This video shows a mirror module configuration with synchronous real-time replication and failover.

The file replication and the failover are configured for Microsoft SQL Server but it works in the same manner for other databases.

Free trial here

Apache Cluster

This video shows a farm module configuration with load balancing and failover.

The load balancing and the failover are configured for Apache but it works in the same manner for other web services.

Free trial here

Hyper-V Cluster

This video shows a Hyper-V cluster with full replications of virtual machines.

Virtual machines can run on both Hyper-V servers and they are restarted in case of failure.

Free trial here

SafeKit Training


  1. Overview / pptx

    • Features
    • Architectures
    • Distinctive advantages
  2. Competition / pptx

    • Hardware vs software cluster
    • Synchronous vs asynchronous replication
    • File vs disk replication
    • High availability vs fault tolerance
    • Hardware vs software load balancing
    • Virtual machine vs application HA

Installation, Console, CLI

  1. Install and setup / pptx

    • Package installation
    • Nodes setup
    • Cluster configuration
    • Upgrade
  2. Web console / pptx

    • Cluster configuration
    • Configuration tab
    • Control tab
    • Monitor tab
    • Advanced Configuration tab
  3. Command line / pptx

    • Silent installation
    • Cluster administration
    • Module administration
    • Command line interface

Advanced configuration

  1. Mirror module / pptx

    • userconfig.xml + restart scripts
    • Heartbeat (<hearbeat>)
    • Virtual IP address (<vip>)
    • Real-time file replication (<rfs>)
  2. Farm  module / pptx

    • userconfig.xml + restart scripts
    • Farm configuration (<farm>)
    • Virtual IP address (<vip>)
  3. Checkers / pptx

    • Failover machine (<failover>)
    • Process monitoring (<errd>)
    • Network and duplicate IP checkers
    • Custom checker (<custom>)
    • Split brain checker (<splitbrain>)
    • TCP, ping, module checkers


  1. Support tools / pptx

    • Analyze snapshots
  2. Evidian support / pptx

    • Get permanent license key
    • Register on support.evidian.com
    • Call desk


  1. Technical documentation

  2. Presales documentation