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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
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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

Partners, the success with SafeKit

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

With many references in many countries won by partners, SafeKit has proven to be the easiest solution to implement for redundancy and high availability of building management, video management, access control, SCADA software...

Building Management Software (BMS)

Video Management Software (VMS)

Electronic Access Control Software (EACS)

SCADA Software (Industry)

SafeKit Modules for Plug&Play Redundancy and High Availability Solutions

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 Overview

Examples of redundancy and high availability solutions with SafeKit.

Full training here

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 Technical Documentation

SafeKit Training


  1. Overview / pptx

    • Demonstration
    • Examples of redundancy and high availability solution
    • Evidian SafeKit sold in many different countries with Milestone
    • 2 solutions: virtual machine or application cluster
    • Distinctive advantages
    • More information on the web site
    • SafeKit training
  2. Competition / pptx

    • Cluster of virtual machines
    • Mirror cluster
    • Farm cluster

Installation, Console, CLI

  1. Install and setup / pptx
    • Package installation
    • Nodes setup
    • Upgrade
  2. Web console / pptx
    • Cluster configuration
    • Configuration tab
    • Control tab
    • Monitor tab
    • Advanced Configuration tab
    • Troubleshooting
  3. Command line / pptx
    • Cluster administration
    • Module administration
    • Control commands
    • Troubleshooting

Advanced configuration

  1. Mirror module / pptx
    • Mirror's states in action
    • start_prim / stop_prim scripts
    • userconfig.xml
    • Heartbeat (<hearbeat>)
    • Virtual IP address (<vip>)
    • Real-time file replication (<rfs>)
    • How real-time file replication works?
    • Troubleshooting
  2. Farm  module / pptx
    • Farm's states in action
    • start_both / stop_both scripts
    • userconfig.xml
    • Farm heartbeats (<farm>)
    • Virtual IP address (<vip>)
    • Troubleshooting

Advanced configuration

  1. Checkers / pptx
    • Checkers in action
    • userconfig.xml
    • errd checker
    • intf and ip checkers
    • custom checker
    • splitbrain checker for a mirror module
    • tcp, ping, module checkers
    • Troubleshooting


  1. Support tools / pptx
    • How to analyze snapshots?
    • Best practises
  2. Evidian support / pptx
    • Get permanent license key
    • Register on support.evidian.com
    • Call desk