SQL Server for Genetec: The Simplest High Availability Cluster with Replication and Failover between Two Redundant Servers

Evidian SafeKit

How the Evidian SafeKit software simply implements a SQL Server high availability cluster for Genetec with real-time synchronous replication and failover between two redundant servers without shared disk

How the Evidian SafeKit mirror cluster implements SQL Server for Genetec high availability with synchronous replication and failover between two redundant servers?

Evidian SafeKit brings high availability to SQL Server for Genetec between two redundant servers. This article explains how to implement quickly a SQL Server for Genetec cluster without shared disk and without specific skills. The high availabity module sqlserver.safe and a free trial are offered in the Installation tab below.

Note that SafeKit is a generic product. You can implement with the same product real-time replication and failover of new directories and services, databases, docker containers, full Hyper-V or KVM virtual machines, Cloud applications. See other examples of mirror modules here.

This clustering solution is recognized as the simplest to implement by our customers and partners. It is also a complete solution that solves

  • hardware failures (20% of problems), including the complete failure of a computer room,
  • software failures (40% of problems), including smooth upgrade server by server,
  • and human errors (40% of problems) thanks to its ease of use, including a very simple administration web console to configure, control and monitor clusters.

On the figure with two redundant servers, the server 1/PRIM runs SQL Server for Genetec services (any edition). Users are connected to the virtual IP address of the mirror cluster.  SafeKit replicates files opened by SQL Server for Genetec services in real time.  Only changes in the files are replicated across the network, thus limiting traffic (byte-level file replication). Names of file directories containing SQL Server for Genetec data are simply configured in SafeKit.  There are no pre-requisites on disk organization for the two servers. Directories to replicate may be located in the system disk. SafeKit implements synchronous replication with no data loss on failure contrary to asynchronous replication.

In case of server 1 failure, there is an automatic failover on server 2 with virtual IP failover and restart of SQL Server for Genetec services. Then, when server 1 is restarted, SafeKit implements automatic failback with reintegration of data without stopping SQL Server for Genetec services on server 2. Finally, the system returns to synchronous replication between server 2 and server 1. The administrator can decide to swap the role of primary and secondary and to run SQL Server for Genetec services on server 1.  The swap can also be done automatically by configuration.

Note that that you can deploy several modules on the same cluster. Each module will have its own virtual IP address and replicated directories. Thus, you can implement active/active cluster with several mirror modules or a mixed of farm and mirror modules.

Free trial + sqlserver.safe module and step by step installation procedure of SafeKit between two redundant SQL Servers for Genetec

Installation of a SafeKit / SQL Server for Genetec high availability cluster with real-time synchronous replication and failover between two redundant servers

Prerequisites

  • you need SQL Server for Genetec installed on 2 nodes (virtual machines or physical servers)
  • on Windows, with Windows services manager, put SQL Server for Genetec services with Boot Startup Type = Manual on both nodes. SafeKit controls start of SQL Server for Genetec services in start_prim. Edit start_prim during the configuration to check if you have put all services in Manual boot including the new ones that you can add.
  • if it is not already done, enable execution of powershell scripts on both nodes

Package installation on Windows

  • Install the free version of SafeKit on 2 Windows nodes with SQL Server for Genetec services installed on both nodes
  • Download the Windows module

    The module contains the files userconfig.xml, start_prim and stop_prim described in the internals tab
  • Put sqlserver.safe under C:\safekit\Application_Modules\demo\ (create the demo directory if it does not exist)
  • To open the Windows firewall, on both nodes start a command line as administrator, goto C:\safekit\private\bin and type  .\firewallcfg.cmd add
  • For synchronizing SafeKit at boot and at shutdown, on both nodes start a command line as administrator, goto C:\safekit\private\bin and type  .\addStartupShutdown.cmd only once

Note    User's guide available here

Go to the Configuration tab

Configuration of a SafeKit / SQL Server for Genetec high availability cluster with real-time synchronous replication and failover between two redundant servers

Configuration instructions

Warning  Important: all the SafeKit configuration is made from a single browser.

Launch the web console in a browser on one node by connecting to http://localhost:9010 (next image). You can also run the console in a browser on an external workstation by connecting to the physical IP address of one node.

Start the SafeKit web console for configuring the SQL Server for Genetec module

Note   To secure the web console, see 11. Securing the SafeKit web console in the User's Guide.

Enter IP address of the first node and click on Confirm (next image)

SafeKit web console - first node in the SQL Server for Genetec cluster

Click on New node and enter IP address of the second node (next image)
Then click on the red floppy disk to save the configuration (next image)

SafeKit web console - second node in the SQL Server for Genetec cluster

Note   In the previous image, the save operation put the IP addresses in the file c:\safekit\var\cluster\cluster.xml and apply the distributed command c:\safekit\safekit –H "*" -G which configures node 1 and node 2. So do not redo this operation on the other node. Check the connectivity and firewall between both nodes for troubleshooting.

In the Configuration tab (next image), click on sqlserver.safe (xxx.safe in the next image) then enter sqlserver as the module name and Confirm (the console finds sqlserver.safe in the 'demo/' directory that you previously filled during the installation)

SafeKit web console - start configuration of SQL Server for Genetec module SafeKit web console - enter SQL Server for Genetec module name

Click on Validate (next image)

SafeKit web console - enter SQL Server for Genetec module nodes

After the click on Validate, this new window appears (next image)

SafeKit web console - enter SQL Server for Genetec parameters

On the previous image:

  • Check that replicated directories are installed on both nodes and contain application data.
    Replication of data and also logs is required for a database.
    You can add new directories to replicate if necessary.
  • Enter a virtual IP address. A virtual IP address is a standard IP address in the same IP network (same subnet) as the IP addresses of both nodes.
    Clients of the application must be configured with the virtual IP address (or the DNS name associated to the virtual IP address).
    The virtual IP address is automatically switched in case of failover.
  • start_prim and stop_prim must contain the start and the stop of the SQL Server for Genetec application.
    Edit the scripts and check that the names of services in these scripts are those installed on your both machines (else modify them in the scripts).
    You can add new services in the scripts if necessary.
  • Stop the services configured in start_prim on both nodes.
  • On Windows and on both nodes, with Windows services manager, put SQL Server for Genetec services set inside start_prim with Boot Startup Type = Manual on both servers (SafeKit controls start of SQL Server for Genetec services in start_prim).
  • Note that if a process name is displayed in Process checker, it will be monitored with the action restart in case of failure. The services will be stopped an restarted locally on the primary server if this process disappears from the list of running processes. After 3 unsuccessful local restarts, the module is stopped on the primary server and the services are restarted on the secondary server.

Click on Validate (previous image)

SafeKit web console - stop the SQL Server for Genetec module before configuration the configuration

Click on Configure (previous image)

SafeKit web console - check the success green message of the SQL Server for Genetec configuration

Check the success green message on both servers and click on Next (previous image).

We assume that node 1 is the referencial with the up-to-date data (otherwise do the following operation on node 2).
We assume that the services started automatically by SafeKit in the start_prim script are stopped on node 1.
Select node 1 and click on start it (next image).
When you will start node 2, the first resynchronization will be made from node1 to node 2.
If in doubt, before this operation, we suggest you to make a copy of replicated directories before starting the cluster to avoid any errors.

SafeKit web console - select the SQL Server for Genetec node with the up-to-date database

node 1 must reach the ALONE (green) state (next image) meaning that the start_prim script has been executed on node 1.
When node 1 reaches the ALONE (green) state, you can check that the SQL Server for Genetec application is started on node 1.
If the state is ALONE (green) and if the application is not started, check the start_prim script: you can find output messages of the script in the Application Log available in the Control tab.
If node 1 does not reach the ALONE (green) state, analyze why with the Module Log available in the Control tab.
Note: in the next image, if the cluster is in the state [WAIT (red) not uptodate - STOP (red) not uptodate], stop the WAIT server and force its start as primary (click here to see the operation).

SafeKit web console - the first SQL Server for Genetec node starts as primary and is alone

We assume that the services started automatically by SafeKit in the start_prim script are stopped on node 2.
Start node 2 (previous image) which becomes SECOND green (next image) after resynchronisation of all replicated directories (binary copy from node 1 to node 2).

SafeKit web console - the second SQL Server for Genetec node starts as SECOND

The cluster is operational with SQL Server for Genetec services running on the PRIM node and nothing running on the SECOND node (previous image). Only modifications inside files are replicated in real-time in this state.

Be careful, components which are clients of the SQL Server for Genetec services must be configured with the virtual IP address. The configuration can be made with a DNS name (if a DNS name has been created and associated with the virtual IP address).

Test

Check with Windows Microsoft Management Console (MMC) that the SQL Server for Genetec services have been started on the primary server by the start_prim script and stopped on the secondary server by the stop_prim script.

Stop the PRIM node by scrolling down the menu of the primary node and by clicking on Stop. Check that there is a failover on the SECOND node. And with Windows Microsoft Management Console (MMC), check the failover of SQL Server for Genetec services (stopped and started in the stop_prim and start_prim scripts).

More information on tests in the User's Guide

Automatic start of the module at boot

Configure boot start (next image on the right side) configures the automatic boot of the module when the server boots. Do this configuration on node1 and node2 once the high availability solution is correctly running.

SafeKit web console - Automatic boot of SQL Server for Genetec module

Note that on Windows, with Windows services manager, we assume that SQL Server for Genetec services are with Boot Startup Type = Manual on both nodes. SafeKit controls start of SQL Server for Genetec services when starting the module in start_prim.

Note that for synchronizing SafeKit at boot and at shutdown, on both nodes, we assume that a command line has been run during installation as administrator: .\addStartupShutdown.cmd in C:\safekit\private\bin (otherwise dot it now only once).

For reading the SafeKit logs, go to the Troubleshooting tab

For editing userconfig.xml, start_prim and stop_prim, go to the Advanced Configuration tab

Troubleshooting of a SafeKit / SQL Server for Genetec high availability cluster with real-time synchronous replication and failover between two redundant servers

Module log

Read the module log to understand the reasons of a failover, of a waiting state on the availability of a resource etc...
To see the module log of the primary server (next image):

  • click on the Control tab
  • click on node 1/PRIM (it becomes blue) on the left side to select the server
  • click on Module Log
  • click on the Refresh icon (green arrows) to update the console
  • click on the floppy disk to save the module log in a .txt file and to analyze in a text editor

Repeat the same operation to see the module log of the secondary server.

SafeKit web console - Module Log of the PRIM SQL Server for Genetec server

Application log

Read the application log to see the output messages of the stat_prim and stop_prim restart scripts.
To see the application log of the primary server (next image):

  • click on the Control tab
  • click on node 1/PRIM (it becomes blue) on the left side to select the server
  • click on Application Log to see messages when starting and stopping SQL Server for Genetec services
  • click on the Refresh icon (green arrows) to update the console
  • click on the floppy disk to save the application log in a .txt file and to analyze in a text editor

Repeat the same operation to see the application log of the secondary server.

SafeKit web console - Application Log of the PRIM SQL Server for Genetec server

More information on troubleshooting in the User's Guide

For support, go to the Support tab

Advanced configuration of a SafeKit / SQL Server for Genetec high availability cluster with real-time synchronous replication and failover between two redundant servers

In Advanced Configuration tab (next image), you can edit internal files of the module: bin/start_prim and bin/stop_prim and conf/userconfig.xml (next image on the left side). 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 (next image): the interface will allow you to redeploy the modified files on both servers.

SafeKit web console - Advanced configuration of SQL Server for Genetec module

More information on userconfig.xml in the User's Guide

For an example of userconfig.xml, start_prim and stop_prim, go to the Internals tab

Support of a SafeKit / SQL Server for Genetec high availability cluster with real-time synchronous replication and failover between two redundant servers

For getting support on the call desk of https://support.evidian.com, get 2 Snaphots (2 .zip files), one for each server and upload them in the call desk tool (next image).

SafeKit web console - SQL Server for Genetec snaphots for support

More information on support in the User's Guide

Internals of a SafeKit / SQL Server high availability cluster for Genetec with synchronous replication and failover

Go to the Advanced Configuration tab, for editing these files

Internal files of the Windows sqlserver.safe module

userconfig.xml (description in the User's Guide)
<!DOCTYPE safe>
<safe>
<service mode="mirror" defaultprim="alone" maxloop="3" loop_interval="24" failover="on">
  <!-- Heartbeat Configuration -->
  <!-- Names or IP addresses on the default network are set during initialization in the console -->
  <heart pulse="700" timeout="30000">
    <heartbeat name="default" ident="flow">
    </heartbeat>
  </heart>
  <!-- Virtual IP Configuration -->
  <!-- Replace
     * VIRTUAL_TO_BE_DEFINED by the name of your virtual server 
  -->
  <vip>
    <interface_list>
        <interface check="on" arpreroute="on"> 
	  <real_interface>
               <virtual_addr addr="VIRTUAL_TO_BE_DEFINED" where="one_side_alias" />
          </real_interface>
        </interface>
    </interface_list>
  </vip>
  <!-- Software Error Detection Configuration -->
  <errd polltimer="10">
    <!-- Microsoft SQL Server process -->
    <proc name="sqlservr.exe" atleast="1" action="restart" class="prim" />
    <proc name="sqlagent.exe" atleast="1" action="restart" class="prim" />
    <proc name="sqlwriter.exe" atleast="1" action="restart" class="prim" />
  </errd>
  <!-- File Replication Configuration -->
  <!-- Replace
     * YOUR_INSTANCE to set the directory of your Microsoft SQL Server database and logs
  -->
  <rfs async="second" acl="off" nbrei="3">
	<replicated dir="C:Program FilesMicrosoft SQL ServerYOUR_INSTANCEMSSQLDATA" mode="read_only" />
	<replicated dir="C:Program FilesMicrosoft SQL ServerYOUR_INSTANCEMSSQLLog" mode="read_only" />
  </rfs>
  <!-- User scripts activation -->
  <user nicestoptimeout="300" forcestoptimeout="300" logging="userlog" />
</service>
</safe>
start_prim.cmd
@echo off
rem Script called on the primary server for starting application services 

rem For logging into SafeKit log use:
rem "%SAFE%safekit" printi | printe "message"

rem stdout goes into Application log
echo "Running start_prim %*" 

set res=0

net start "MSSQLServer" > nul
if not %errorlevel% == 0 (
  %SAFE%safekit printi "MSSQLServer start failed"
) else (
  %SAFE%safekit printi "MSSQLServer started"
)

net start "SQLServerAgent" > nul
if not %errorlevel% == 0 (
  %SAFE%safekit printi "SQLServerAgent start failed"
) else (
  %SAFE%safekit printi "SQLServerAgent started"
)

net start "SQLWriter" > nul
if not %errorlevel% == 0 (
  %SAFE%safekit printi "SQLWriter start failed"
) else (
  %SAFE%safekit printi "SQLWriter started"
)

if %res% == 0 goto end

:stop
set res=%errorlevel%
"%SAFE%safekit" printe "start_prim failed"

rem uncomment to stop SafeKit when critical
rem "%SAFE%safekit" stop -i "start_prim"

:end
stop_prim.cmd
@echo off
rem Script called on the primary server for stopping application services 

rem ----------------------------------------------------------
rem
rem 2 stop modes:
rem
rem - graceful stop
rem   call standard application stop with net stop
rem
rem - force stop (%1=force)
rem   kill application's processes
rem
rem ----------------------------------------------------------

rem For logging into SafeKit log use:
rem "%SAFE%safekit" printi | printe "message"

rem stdout goes into Application log
echo "Running stop_prim %*" 

set res=0

rem default: no action on forcestop
if "%1" == "force" goto check

rem %SAFE%safekit printi "Stopping SQLWriter..."
rem net stop "SQLWriter" /Y > nul

rem %SAFE%safekit printi "Stopping SQLServerAgent..."
rem net stop "SQLServerAgent" /Y > nul

%SAFE%safekit printi "Stopping MSSQLServer..."
net stop "MSSQLServer" /Y > nul

rem wait a little for a real stop of services
%SAFEBIN%sleep 10
goto end

:check

rem call :checksrv "SQLWRITER"
rem call :checksrv "SQLServerAgent"
call :checksrv "MSSQLServer"

goto end

:checksrv
 set SERVICE=%1
 net stop %SERVICE% /Y  
 if NOT ERRORLEVEL 1 goto end
 sc query %SERVICE% | findstr STATE | findstr 1
 if NOT ERRORLEVEL 1 goto end
 "%SAFE%safekit" stop -i "stop_prim : service not stopped" 
 exit


:end

Customers of SafeKit High Availability Software in all Business Activities

  • Best high availability use cases with SafeKit

    Best use cases [+]

    Like   OEM Software Like   Distributed Enterprise Like   Remote Sites
    Application Clustering Software for a Software Publisher High Availability Software in a Distributed Enterprise Business Continuity and Disaster Recovery without a replicated SAN
    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

    Like  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.

    Like  The product very easy to deploy for a reseller

    “WithNCompany has deployed in South Korea many SafeKit high availability solutions with the Hanwha Video Surveillance Platform. SafeKit is appreciated because the product is easy to install and very quickly deployed.”

    Like  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 and Marseille metro lines (the control rooms).”


  • High availability of Video Surveillance Platforms with SafeKit

    Video surveillance and access control [+]

    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."

    Use cases:


  • Harmonic has deployed more than 80 SafeKit clusters for high availability of its TV broadcasting application over satellites, terrestrials, cable, IPTV.

    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.”


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

    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.


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

    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 systems supplier, Copperchase, deploys SafeKit high availability in airports.

    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."


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

    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."


  • 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.

    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.”


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

    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."


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

    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 High Availability Differentiators against Competition

Evidian SafeKit mirror cluster with real-time file replication and failover

3 products in 1 >

3 products in 1

Like  SafeKit high availability software on Windows and Linux saves on 1/ costly external shared or replicated storage, 2/ load balancing boxes, 3/ enterprise editions of OS and databases

Like  SafeKit includes all clustering features: synchronous real-time file replication, monitoring of server / network / software failures, automatic Microsoft SQL Server restart, virtual IP address switched in case of failure to reroute clients

Very simple configuration >

Simple configuration with a web console

Like   The cluster configuration is very simple and made with the sqlserver.safe module. New services and new replicated directories can be added to an existing application module to complete a high availability solution

Like   All the configuration of clusters is made using a simple centralized web administration console

Like   There is no domain controller or active directory to configure as with Microsoft cluster

Synchronous replication >

Synchronous replication

Like  The real-time replication is synchronous with no data loss on failure

Dislike  This is not the case with asynchronous replication

Fully automated failback procedure >

Automatic failback

Like  After a failure when a server reboots, the replication failback procedure is fully automatic and the failed server reintegrates the cluster without stopping Microsoft SQL Server on the only remaining server

Dislike  This is not the case with most replication solutions particularly with replication at the database level. Manual operations are required for resynchronizing a failed server. Microsoft SQL Server may even be stopped on the only remaining server during the resynchonization of the failed server

Replication of any type of data >

Any replicated data

Like  The replication is working for Microsoft SQL Server but also for any files which shall be replicated

Dislike  This not the case for replication at the database level

File replication vs disk replication >

File replication vs disk replication

Like  The replication is based on file directories that can be located anywhere (even in the system disk)

Disike  This is not the case with disk replication where special Microsoft SQL Server configuration must be made to put the application data in a special disk

File replication vs shared disk >

File replication vs shared disk

Like  The servers can be put in two remote sites

Dislike  This is not the case with shared disk solutions

Remote sites and virtual IP address >

Remote sites

Like  All SafeKit clustering features are working for 2 servers in remote sites. Replication requires an extended LAN type network (latency = performance of synchronous replication, bandwidth = performance of resynchronization after failure).

Like  If both servers are connected to the same IP network through an extended LAN between two remote sites, the virtual IP address of SafeKit is working with rerouting at level 2

Like  If both servers are connected to two different IP networks between two remote sites, the virtual IP address can be configured at the level of a load balancer with the "healh check" of SafeKit.

Quorum >

Quorum

Like  The solution works with only 2 servers and for the quorum (network isolation between both sites), a simple split brain checker to a router is offered to support a single execution of the critical application

Like  This is not the case for most clustering solutions where a 3rd server is required for the quorum

Active/active cluster >

Active active mirror cluster

Like  The secondary server is not dedicated to the restart of the primary server. The cluster can be active-active by running 2 different mirror modules

Dislike  This is not the case with a fault-tolerant system where the secondary is dedicated to the execution of the same application synchronized at the instruction level

Uniform high availability solution >

Uniform high availability solution

Like  SafeKit implements a mirror cluster with replication and failover. But it imlements also a farm cluster with load balancing and failover.

Like  Thus a N-tiers architecture can be made highly available and load balanced with the same solution on Windows and Linux (same installation, configuration, administration with the SafeKit console or with the command line interface). This is unique on the market

Dislike  This is not the case with an architecture mixing different technologies for load balancing, replication and failover

RTO / RPO >

Simple configuration with a web console

Like  SafeKit implements quick Microsoft SQL Server restart in case of failure: around 1 mn or less (see RTO/RPO here)

Dislike  Quick Microsoft SQL Server restart is not ensured with full virtual machines replication. In case of hypervisor failure, a full VM must be rebooted on a new hypervisor with a recovery time depending on the OS reboot as with VMware HA or Hyper-V cluster

Software clustering vs hardware clustering >

A software cluster with SafeKit installed on two servers

Like  A simple software cluster with the SafeKit package just installed on two servers

Hardware clustering with external shared storage

Dislike  Complex hardware clustering with external storage or network load balancers

Shared nothing vs a shared disk cluster >

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

Like  SafeKit is a shared-nothing cluster: easy to deploy even in remote sites

Shared disk cluster: complex to deploy

Dislike  A shared disk cluster is complex to deploy

Application High Availability vs Full Virtual Machine High Availability >

SafeKit application high availability supports hardware failure, software failure, human errors

Like  Application HA supports hardware failure and software failure with a quick recovery time (RTO around 1 mn or less).
Smooth upgrade of application and OS possible server by server (version N and N+1 can coexist)

Virtual machines high availability supports only hardware failure with an recovery time depending on the OS reboot

Dislike  Full virtual machines HA supports only hardware failure with a VM reboot and a recovery time depending on the OS reboot.
Smooth upgrade not possible

High availability vs fault tolerance >

SafeKit high availability vs fault-tolerance

Like  No dedicated server with SafeKit. Each server can be the failover server of the other one.
Software failure with restart in another OS environment.
Smooth upgrade of application and OS possible server by server (version N and N+1 can coexist)

Fault tolerance system

Dislike  Secondary server dedicated to the execution of the same application synchronized at the instruction level.
Software exception on both servers at the same time.
Smooth upgrade not possible

Synchronous replication vs asynchronous replication >

SafeKit synchronous replication with no data in case of failure

Like  SafeKit implements real-time synchronous replication with no data loss in case of failure

Asynchronous replication with data loss on failure

Dislike  With asynchronous replication, there is data loss on failure

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

SafeKit cluster with byte-level file replication: simply replicates directories even in the system disk

Like  SafeKit implements real-time byte-level file replication and is simply configured with application directories to replicate even in the system disk

Cluster with block-level disk replication: complex and require to put application data in a special disk

Dislike  Block-level disk replication is complex to configure and requires to put application data in a special disk

Heartbeat, failover and quorum to avoid 2 master nodes >

Simple quorum in a SafeKit cluster with a split brain checker configured on a router

Like  To avoid 2 masters, SafeKit proposes a simple split brain checker configured on a router

Complex quorum in other clusters: third machine, special quorum disk, remote hardware reset

Dislike  To avoid 2 masters, other clusters require a complex configuration with a third machine, a special quorum disk, a special interconnect

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

No special network configuration in a SafeKit cluster

Like  No dedicated proxy servers and no special network configuration are required in a SafeKit cluster for virtual IP addresses

Special network configuration in other clusters

Dislike  Special network configuration is required in other clusters for virtual IP addresses. Note that SafeKit offers a health check adapted to load balancers

Demonstrations of SafeKit High Availability Software

SafeKit Webinar

This webinar presents in 10 minutes Evidian SafeKit.

In this webinar, you will understand:

  • mirror and farm clusters
  • cost savings against hardware clustering solutions
  • best use cases
  • the integration process for a new application

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

Free On-Line Training on SafeKit High Availability Software

SafeKit Modules for Plug&Play High Availability Solutions