EvidianSystel
ProfileA software integrator deploys Evidian’s SafeKit high-availability
solution in firefighter and emergency medical services call centers.

• Systel (www.systel-fr.com) is
an integrator specialized insolutions for fire andemergency services.

Making a multi-platform application suite highly available
Systel needs high availability for its critical solutions:

Users• Ensuring 24x7 availability of its application suite meant for EMS and firefighters’
emergency call centers,• Having the same multi-platform clustering solution for its software solutions in Windowsand Linux,• Being able to isolate the servers in distinct rooms so as to protect them from fire-induced
damage, for example.

• Firefighters and EMS use
Systel’s suite in call centersof 42 administrative
departments in France,
where speed of response
can be life-saving.

To solve these constraints, Systel has chosen SafeKit, Evidian’s software-only clusteringsolution.

Challenges• Deploying a Windows andLinux high-availability
solution with Systel’sapplication suite in France

Integrated high-availability solution
Systel deploys its application suite on two standard Windows or Linux servers without shareddisks, as follows:• Systel’s software suite, including either Oracle Standard Edition or Microsoft SQL Server,is installed on each server,• SafeKit, the software clustering solution, is installed on each server,• A customized SafeKit module for Systel: real-time application data replication over thenetwork, failure recovery and automatic change of virtual IP address.

Benefits• Integrated software highavailability solution basedon SafeKit,• Clustering solution
independent of thehardware,• Standard servers, without
shared disks, placed inseparate rooms for fireprotection.

Thus, with SafeKit, the emergency call centers (fire departments, EMS, etc.) equipped by Systel
have a user-friendly, failure-tolerant solution. Moreover, Systel’s customers save the cost ofshared disks and Business editions of operating systems and databases.

•Systelnow

Case study > Software vendor and high availability

www.evidian.com

Deployment of a SafeKit cluster at Systel
Phase 1. Normal status.
Server 1 runs the application. SafeKit replicates on server 2, inreal time over the network, the files opened by the application.
Only the modifications made by the application are replicated,
thereby limiting the traffic.
There are no prerequisites in terms of server organization. For example, the files may be on aRAID5 disk on server 1 and on a simple disk on server 2.
“SafeKit perfectly meets theneeds of a software vendor. Its
main advantage is that it bringsin high availability through asoftware option that is added toour own multi-platform software
suite. This way, we are notdependent on a specific andcostly hardware clusteringsolution that is not only difficult
to install and maintain, but also
differs according to client
environments. With SafeKit, ourfirefighter call centers are runwith an integrated software
clustering solution, which is thesame for all our customers, isuser friendly and for which wemaster the installation up toafter-sales support.”
Marc Pellas,
CEO,Systel.

Thanks to the synchronous replication of write operations on both servers, no data is lost incase of failure. Therefore, any set of data committed by a transactional application like
Oracle is stored on the secondary server. (This possibility is not offered by products that
implement asynchronous replication)..

Phase 2. Switchover in case of failure.
If server 1 fails, SafeKit ensures switchover to server 2. SafeKit
switches the cluster’s virtual IP address and starts the application
on server 2. The application retrieves the replicated files: nowrite operation on the disk is lost between server 1 and server 2.
Switchover timeout is equal to the failure detection timeout (30 seconds by default) plus theapplication restart time. (There is no timeout for returning or recovering the file system on thesecondary server, as is the case with disk replication solutions).

Phase 3. Failure recovery.
When server 1 is restarted, SafeKit re-synchronizes the files
automatically. Only the files modified on server 2 when server 1
was inactive are resynchronized. Server 1 is resynchronizedwithout stopping the applications on server 2.
After this re-synchronization, the system is again highly available. The files are again in mirror
mode; the only difference is that the application runs on server 2, with server 1 as backup.
If the administrator wants his or her application to rather run on server 1, he or she makes theswitchover manually, with a simple mouse click, or automatically.

39 A2 30LV 02

For more information: www.evidian.com© Eviden. Evidian is the registered trademark of Eviden. All products, brand names, service marks, trademarks and other names
mentioned in this document are proprietary to their respective owners and are protected by applicable trademark and copyright laws.
Evidian reserves the right to modify the characteristics of its products without prior notice.