Evidian SafeKit brings high availability to Siemens Desigo CC between two redundant servers.
This article explains how to implement quickly a Siemens Desigo CC cluster without shared disk and without specific skills.
The principle of the solution is to put Siemens Desigo CC in a virtual machine under Hyper-V. SafeKit implements real-time replication and automatic failover of the virtual machine.
A free trial and the high availability module for Hyper-V and Siemens Desigo CC are offered in this article.
Other applications can be put in other virtual machines with crossed replication and mutual takeover. With this solution, there is no need to configure restart scripts and define virtual IP addresses for each application.
Note that SafeKit is a generic product on Windows and Linux.
You can implement with the same product real-time replication and failover of any file directory and service, database, complete Hyper-V or KVM virtual machines, Docker, Kubernetes , Cloud applications.
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.
The following steps are described for one virtual machine containing Siemens Desigo CC 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.
Server 1 (PRIM) runs the VM (virtual machine) containing Siemens Desigo CC. 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.
When Server 1 fails, Server 2 takes over. SafeKit restarts the VM containing Siemens Desigo CC 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.
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 containing Siemens Desigo CC 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.
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.
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.
Resynchronization time after a failure (step 3)
Download the free version of SafeKit on 2 Windows nodes.
Note: the free version includes all SafeKit features. At the end of the trial, you can activate permanent license keys without uninstalling the package.
To open the Windows firewall, on both nodes start a command line as administrator, goto C:\safekit\private\bin and type
For synchronizing SafeKit at boot and at shutdown, on both nodes start a command line as administrator, goto C:\safekit\private\bin and type only once
Download the hyperv.safe module.
The module is free. It contains the files userconfig.xml and the restart scripts.
The Hyper-V configuration is presented with a virtual machine named VM1 and containing the application to restart in case of failure.
You will have to repeat this configuration for all VMs that you want to replicate and to restart. SafeKit supports up to 25 virtual machines.
The VM1 virtual machine files (VM1 configuration file, virtual hard disk...) must be put in a same folder: this folder will be replicated by SafeKit.
Make sure the virtual switch name(s) referenced by the virtual machine exist on both Hyper-V servers and corresponds to the same physical network.
If all the files of VM1 are not in the same folder, use Hyper-V manager:
You can also run the console in a browser on a workstation external to the cluster.
The configuration of SafeKit is done on both nodes from a single browser.
To secure the web console, see 11. Securing the SafeKit web console in the User's Guide.
If node1 or node2 background color is red, check connectivity of the browser to both nodes and check firewall on both nodes for troubleshooting.
This operation will place the IP addresses in the
cluster.xml file on both nodes (more information in the training with the command line).
We assume that all VM1 files are in D:\Repli-Hyper-V\VM1\ (see prerequisites). This directory will be replicated in real-time by SafeKit.
The NORMAL_STOP and FORCE_STOP values can be "stop", "save" or "off":
"stop" is recommended because it causes the shutdown then the reboot of the VM when the module is stopped and restarted. Thus the application inside the VM is restarted.
This will be the case, for example, when switching between primary and secondary roles.
This operation will report the configuration in the
userconfig.xml file on both nodes (more information in the training with the command line).
VM1\replicated directory, select it and start it.
When node 2 will be started, all data in
VM1\ will be copied from node 1 to node 2.
If you make the wrong choice, you run the risk of synchronizing outdated data on both nodes.
It is also assumed that the VM1 virtual machine is stopped on node 1 so that SafeKit installs the replication mechanisms and then starts VM1 in the
start_primscript has been executed on node 1.
If the status is ALONE (green) and VM1 is not started, check output messages of
start_prim in the Application Log of node 1.
If node 1 does not reach ALONE (green) state, analyze why with the Module Log of node 1.
If the cluster is in
WAIT (red) not uptodate - STOP (red) not uptodate state, stop the WAIT node and force its start as primary.
Node 2 should go to SECOND (green) after resynchronizing the
VM1\ replicated directory (binary copy from node 1 to node 2).
This may take a while depending on the size of
VM1\ and the network bandwidth.
If node 2 does not reach SECOND (green), analyze why with the Module Log of node 2.
If VM1 is not started on node 2 while the state is ALONE (green), check the output messages of the
start_prim script in the Application Log of node 2.
start_prim script imports the virtual machine on node 2, the failover can fail because of Hyper-V settings (see this article).
If ALONE (green) is not reached, analyze why with the Module Log of node 2.
To see the module log of node 1 (image):
Click on node2 to see the module log of the secondary server.
To see the application log of node1 (image):
Click on node 2 to see the application log of the secondary server.
If you make change in the internal files here, you must apply the new configuration by a right click on the icon/xxx on the left side (see image): the interface will allow you to redeploy the modified files on both servers.
Network load balancing and failover
|Generic farm >||Generic farm >|
|Microsoft IIS >||-|
|NGINX >||NGINX >|
|Apache >||Apache >|
|Amazon AWS farm >||Amazon AWS farm >|
|Microsoft Azure farm >||Microsoft Azure farm >|
|Google GCP farm >||Google GCP farm >|
|Other cloud >||Other cloud >|
Several modules can be deployed on the same cluster. Thus, advanced clustering architectures can be implemented:
Real-time file replication and failover
|Generic mirror >||Generic mirror >|
|Microsoft SQL Server >||-|
|Oracle >||Oracle >|
|MariaDB >||MariaDB >|
|MySQL >||MySQL >|
|PostgreSQL >||PostgreSQL >|
|Firebird >||Firebird >|
|Windows Hyper-V >||-|
|-||Linux KVM >|
|Milestone XProtect >||-|
|Genetec SQL Server >||-|
|Hanwha Wisenet >||-|
|Nedap AEOS >||-|
Siemens Desigo CC >
Siemens SiPass >
Siemens SIPORT >
Siemens Siveillance >
Bosch AMS >
Bosch BIS >
Bosch BVMS >
|Amazon AWS mirror >||Amazon AWS mirror >|
|Microsoft Azure mirror >||Microsoft Azure mirror >|
|Google GCP mirror >||Google GCP mirror >|
|Other cloud >||Other cloud >|
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.
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.
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.
|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|
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).”
In video surveillance systems and access control, Evidian SafeKit implements high availability with synchronous replication and failover of
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."
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.”
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.
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.”
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."
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."
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.”
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."
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 with the Hyper-V module or the KVM module||Microsoft Hyper-V Cluster & VMware HA|
|No shared disk - synchronous real-time replication instead with no data loss||Shared disk and specific extenal bay of disk|
|Remote sites = no SAN for replication||Remote sites = replicated bays of disk across a SAN|
|No specific IT skill to configure the system||Specific IT skills to configure the system|
Note that the Hyper-V/SafeKit and KVM/SafeKit solutions are limited to replication and failover of 25 VMs.
|VM HA with the SafeKit Hyper-V or KVM module||Application HA with SafeKit application modules|
SafeKit inside 2 hypervisors
SafeKit replication and failover of full VM
SafeKit inside 2 virtual or physical machines
SafeKit replication and failover at application level
|Replicates more data (App+OS)||Replicates only application data|
Reboot of VM on hypervisor 2 if hypervisor 1 crashes
Recovery time depending on the OS reboot
Quick recovery time with restart of App on OS2 if crash of server 1
Around 1 mn or less (see RTO/RPO here)
Application checker and software failover
|Generic solution for any application / OS||Restart scripts to be written in application modules|
A simple software cluster with the SafeKit package just installed on two servers
Complex hardware clustering with external storage or network load balancers
SafeKit is a shared-nothing cluster: easy to deploy even in remote sites
A shared disk cluster is complex to deploy
Application HA supports hardware failure and software failure with a quick recovery time (RTO around 1 mn or less).
Application HA requires to define restart scripts per application and folders to replicate (SafeKit application modules).
Full virtual machines HA supports only hardware failure with a VM reboot and a recovery time depending on the OS reboot.
No restart scripts to define with full virtual machines HA (SafeKit hyperv.safe or kvm.safe modules). Hypervisors are active/active with just multiple virtual machines.
No dedicated server with SafeKit.
Each server can be the failover server of the other one.
Secondary server dedicated to the execution of the same application synchronized at the instruction level.
SafeKit implements real-time synchronous replication with no data loss in case of failure
With asynchronous replication, there is data loss on failure
SafeKit implements real-time byte-level file replication and is simply configured with application directories to replicate even in the system disk
Block-level disk replication is complex to configure and requires to put application data in a special disk
To avoid 2 masters, SafeKit proposes a simple split brain checker configured on a router
To avoid 2 masters, other clusters require a complex configuration with a third machine, a special quorum disk, a special interconnect
No dedicated proxy servers and no special network configuration are required in a SafeKit cluster for virtual IP addresses
Special network configuration is required in other clusters for virtual IP addresses. Note that SafeKit offers a health check adapted to load balancers