Hyper-V: the simplest high availability cluster between two redundant servers without shared disk

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 high availability option easy to deploy to many customers.

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

How the SafeKit Hyper-V cluster works?

The following steps are described for one virtual machine inside one mirror module. Each replicated virtual machine runs in an independent mirror module (with a maximum of 25 virtual machines) with a primary server that can be either the Hyper-V server 1 or the Hyper-V server 2.

Step 1. Real-time replication

Server 1 (PRIM) runs the VM (virtual machine). SafeKit replicates in real time the VM files (virtual hard disk, VM configuration). Only changes made in the files are replicated across the network.

The replication is synchronous with no data loss on failure contrary to asynchronous replication.

You just have to configure the VM directory name in SafeKit. There are no pre-requisites on disk organization. The directory may be located in the system disk.

Step 2. Automatic failover

When Server 1 fails, Server 2 takes over. SafeKit restarts the VM on Server 2. Hyper-V finds the files replicated by SafeKit uptodate on Server 2. 

The VM continues to run on Server 2 by locally modifying its files that are no longer replicated to Server 1.

The failover time is equal to the fault-detection time (set to 30 seconds by default) plus the VM reboot time. 

Step 3. Automatic failback

Failback involves restarting Server 1 after fixing the problem that caused it to fail. SafeKit automatically resynchronizes the VM files.

Failback takes place without disturbing the VM, which can continue running on Server 2.

Step 4. Back to normal

After reintegration, the VM files are once again in mirror mode, as in step 1. The system is back in high-availability mode, with the VM running on Server 2 and SafeKit replicating file updates to Server 1.

If the administrator wishes the VM to run on Server 1, he/she can execute a "swap" command either manually at an appropriate time, or automatically through configuration.

Choose between high availability at the application level or at the virtual machine level

High availability at the application level

In this type of solution, only application data are replicated. And only the application is restared in case of failure. Restart scripts must be written to restart the application. This solution is platform agnostic and works with physical machines, virtual machines, in the Cloud.

We deliver application modules to implement this type of solution. They are preconfigured for well known applications and databases. You can customize them with your own services, data to replicate, application checkers. And you can combine application modules to build advanced multi-level architectures.

High availability at the virtual machine level

In this type of solution, the full Virtual Machine (VM) is replicated (Application + OS). And the full VM is restarted in case of failure. The advantage is that there is no restart scripts to write per application and no virtual IP address to define. If you do not know how the application works, this is the best solution.

We deliver two modules for implementing this solution: one for Hyper-V on Windows and one for KVM on Linux. Several VMs can be replicated and can run on both hypervisors with crossed replication and mutual takeover.

Typical usage with SafeKit

Why a replication of a few Tera-bytes?

Resynchronization time after a failure (step 3)

• 1 Gb/s network ≈ 3 Hours for 1 Tera-bytes.
• 10 Gb/s network ≈ 1 Hour for 1 Tera-bytes or less depending on disk write performances.

Alternative

• For a large volume of data, use external shared storage with a hardware clustering solution.
• More expensive, more complex.

Why a replication < 1,000,000 files?

• Resynchronization time performance after a failure (step 3).
• Time to check each file between both nodes.

Alternative

• Put the many files to replicate in a virtual hard disk / virtual machine.
• Only the files representing the virtual hard disk / virtual machine will be replicated and resynchronized in this case.

Why a failover < 25 replicated VMs?

• Each VM runs in an independent mirror module.
• Maximum of 25 mirror modules running on the same cluster.

Alternative

• Use an external shared storage and another VM clustering solution.
• More expensive, more complex.

Why a LAN/VLAN network between remote sites?

• Automatic failover of the virtual IP address with 2 nodes in the same subnet.
• Good bandwidth for resynchronization (step 3) and good latency for synchronous replication (a few ms).

Alternative

• Use a load balancer for the virtual IP address if the 2 nodes are in 2 subnets (supported by SafeKit, especially in the cloud).
• Use backup solutions with asynchronous replication for high latency network.

SafeKit Modules for Plug&Play High Availability Solutions

Note:

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

• the farm+mirror cluster built by deploying a farm module and a mirror module on the same cluster,
• the active/active cluster with replication built by deploying several mirror modules on 2 servers,
• the Hyper-V cluster or KVM cluster with real-time replication and failover of full virtual machines between 2 active hypervisors,
• the N-1 cluster built by deploying N mirror modules on N+1 servers.

Demonstrations of SafeKit High Availability Software

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

Customers of SafeKit High Availability Software in all Business Activities

• 

  Best use cases [+]

  OEM Software	Distributed Enterprise	Remote Sites
  A software publisher uses SafeKit as an OEM software for high availability of its application	A distributed enterprise deploys SafeKit in many branches without specific IT skills	SafeKit is deployed in two remote sites without the need for replicated bays of disks through a SAN

  Testimonials

  The ideal product for a software publisher

  “SafeKit is the ideal application clustering solution for a software publisher. We currently have deployed more than 80 SafeKit clusters worldwide with our critical TV broadcasting application.”

  The product very easy to deploy for a reseller

  “Noemis, a value added distributor of Milestone Video Surveillance, has assisted integrators to deploy the SafeKit redundancy solution on many projects such as city surveillance, datacenters, stadiums and other critical infrastructures. SafeKit is a great product, and Evidian provides a great support.”

  The product to gain time for a system integrator

  “Thanks to a simple and powerful product, we gained time in the integration and validation of our critical projects like the supervision of Paris metro lines (the control rooms).”

  
  
• 

  Video surveillance and access control [+]

  In video surveillance systems and access control, Evidian SafeKit implements high availability with synchronous replication and failover of

  • Milestone XProtect,
  • Hanwha Wisenet SSM,
  • Siemens CCTV Video Surveillance and Access Control (SiPass)
  • Nedap, TIL Technologies, Synchronic...

  Sebastien Temoin, Technical and Innovation Director, NOEMIS, value added distributor of Milestone solutions:

  "SafeKit by Evidian is a professional solution making easy the redundancy of Milestone Management Server, Event Server, Log Server. The solution is easy to deploy, easy to maintain and can be added on existing installation. We have assisted integrators to deploy the solution on many projects such as city surveillance, datacenters, stadiums and other critical infrastructures. SafeKit is a great product, and Evidian provides great support. Happy to help if you have any questions."

  Use cases:

  • Many partners deploy high availability of the Milestone video surveillance platform with SafeKit.
  • In South Korea, WithNCompany deploys high availability of the Hanwha Video Surveillance platform with SafeKit.

  
  
• 

  TV broadcasting [+]

  Harmonic is using SafeKit as a software OEM high availability solution and deploys it with its TV broadcasting solutions over satellites, terrestrials, cable, IPTV.

  Over 80 SafeKit clusters are deployed on Windows for replication of Harmonic database and automatic failover of the critical application.

  Philippe Vidal, Product Manager, Harmonic says:

  “SafeKit is the ideal application clustering solution for a software publisher looking for a simple and economical high availability software. We are deploying SafeKit worldwide and we currently have more than 80 SafeKit clusters on Windows with our critical TV broadcasting application through terrestrial, satellite, cable and IP-TV. SafeKit implements the continuous and real-time replication of our database as well as the automatic failover of our application for software and hardware failures. Without modifying our application, it was possible for us to customize the installation of SafeKit. Since then, the time of preparation and implementation has been significantly reduced.”

  
  
• 

  Finance [+]

  The European Society of Warranties and Guarantees in Natixis uses SafeKit as a high availability solution for its applications.

  Over 30 SafeKit clusters are deployed on Unix and Windows in Natixis.

  
  
• 

  Industry [+]

  Fives Syleps implements high availability of its ERP with SafeKit and deploys the solution in the food industry.

  Over 20 SafeKit clusters are deployed on Linux and Windows with Oracle.

  Testimonial of Fives Syleps:

  "The automated factories that we equip rely on our ERP. It is not possible that our ERP is out of service due to a computer failure. Otherwise, the whole activity of the factory stops.

  We chose the Evidian SafeKit high availability product because it is an easy to use solution. It is implemented on standard servers and does not require the use of shared disks on a SAN and load balancing network boxes.

  It allows servers to be put in remote computer rooms. In addition, the solution is homogeneous for Linux and Windows platforms. And it provides 3 functionalities: load balancing between servers, automatic failover and real-time data replication.”

  
  

• 

  Air traffic control [+]

  Air traffic control systems supplier, Copperchase, deploys SafeKit high availability in airports.

  Over 20 SafeKit clusters are deployed on Windows.

  Tony Myers, Director of Business Development says:

  "By developing applications for air traffic control, Copperchase is in one of the most critical business activities. We absolutely need our applications to be available all the time. We have found with SafeKit a simple and complete clustering solution for our needs. This software combines in a single product load balancing, real time data replication with no data loss and automatic failover. This is why, Copperchase deploys SafeKit for air traffic control in airports in the UK and the 30 countries where we are present."

  
  
• 

  Bank [+]

  Software vendor Wellington IT deploys SafeKit high availability with its banking application for Credit Unions in Ireland and UK.

  Over 25 SafeKit clusters are deployed on Linux with Oracle.

  Peter Knight, Sales Manager says:

  "Business continuity and disaster recovery are a major concern for our Locus banking application deployed in numerous Credit Unions around Ireland and the UK. We have found with SafeKit a simple and robust solution for high availability and synchronous replication between two servers with no data loss. With this software solution, we are not dependent on a specific and costly hardware clustering solution. It is a perfect tool to provide a software high availability option to an application of a software vendor."

  
  
• 

  Transport [+]

  Paris transport company (RATP) chose the SafeKit high availability and load balancing solution for the centralized control room of line 1 of the Paris subway.

  20 SafeKit clusters are deployed on Windows and Linux.

  Stéphane Guilmin, RATP, Project manager says:

  "Automation of line 1 of the Paris subway is a major project for RATP, requiring a centralized command room (CCR) designed to resist IT failures. With SafeKit, we have three distinct advantages to meet this need. Firstly, SafeKit is a purely software solution that does not demand the use of shared disks on a SAN and network boxes for load balancing. It is very simple to separate our servers into separate machine rooms. Moreover, this clustering solution is homogeneous for our Windows and Linuxplatforms. SafeKit provides the three functions that we needed: load balancing between servers, automatic failover after an incident and real time data replication."

  And also, Philippe Marsol,  Atos BU Transport, Integration Manager says:

  “SafeKit is a simple and powerful product for application high availability. We have integrated SafeKit in our critical projects like the supervision of Paris metro Line 4 (the control room) or Marseille Line 1 and Line 2 (the operations center). Thanks to the simplicity of the product, we gained time for the integration and validation of the solution and we had also quick answers to our questions with a responsive Evidian team.”

  
  
• 

  Healthcare [+]

  The software integrator Systel deploys SafeKit high-availability solution in firefighter and emergency medical call centers.

  Over 30 SafeKit clusters are deployed on Windows with SQL Server.

  Marc Pellas, CEO says:

  "SafeKit perfectly meets the needs of a software vendor. Its main advantage is that it brings in high availability through a software option that is added to our own multi-platform software suite. This way, we are not dependent on a specific and costly hardware clustering solution that is not only difficult to install and maintain, but also differs according to client environments. With SafeKit, our firefighter call centers are run with an integrated software clustering solution, which is the same for all our customers, is user friendly and for which we master the installation up to after-sales support."

  
  
• 

  Government [+]

  ERP high availability and load balancing of the French army (DGA) are made with SafeKit.

  14 SafeKit clusters are deployed on Windows and Linux.

  Alexandre Barth, Systems administrator says:

  "Our production team implemented the SafeKit solution without any difficulty on 14 Windows and Linux clusters. Our critical activity is thus secure, with high-availability and load balancing functions. The advantages of this product are easy deployment and administration of clusters, on the one hand, and uniformity of the solution in the face of heterogeneous operating systems, on the other hand."

   

  
  

SafeKit Training

Introduction

1. Overview / pptx
2. Competition / pptx

Installation, Set-up, Administration

3. Install and setup / pptx
4. Web console / pptx
5. Command line / pptx

Features

6. Mirror module / pptx
7. Farm  module / pptx
8. Checkers / pptx

Support

9. Support tools / pptx
10. Evidian support / pptx

Documentation

• Preconfigured modules
• Data sheet
• Technical overview (docx)
• User's Guide HTML (PDF)
• Release notes
• Software release bulletin