Stoas Learning, a knowledge center for technology and didactics, develops, implements and supports powerful information systems for education and e-learning applications for education, government and organizations. E-learning applications can be implemented at the customer location or used as a hosted service. Stoas Learning, located in Wageningen in the Netherlands, has about 125 employees.
Before the virtualization era, Stoas Learning bought and installed one or two customer-financed servers for each school or customer solution. Many systems were underutilized and there was no redundancy of failover. In 2003, Stoas Learning started a successful virtualization project with three servers and a SAN to run workloads for customers in a production, test or development environment and consolidate the environment. However, the virtualized environment grew very fast and thus became very complex and got out of control. The continuously growing SAN became overloaded and the problem was not recognized by the manufacturer.
“We were struggling with our own success. In the early days of server virtualization, the choice for the technology was more tactical than strategic. The popularity of the concept resulted in VM sprawl instead of consolidation,” said Harold Speeks, IT manager at Stoas Learning. “After five years of growth in the physical and virtual infrastructure, we decided early 2009 to professionalize IT on all possible levels. On one side we needed to consolidate servers and simplify system management, but on the other side we needed to improve service levels to our customers by adding high availability and be able to grow in the hosting branch.”
Stoas Learning looked at all available commercial and open source hypervisors. Where one commercial product was too expensive and had too many unnecessary features, another product was lacking support or a user-friendly graphical interface.
For a long time, Stoas Learning had been running an early version of Citrix® XenApp™ on which Oracle developers test applications for Oracle, and went to 2-Systems, a Gold Citrix Solution Advisor, for advice on upgrading its IT. 2-Systems recommended Citrix® XenServer® and installed the first three XenServer hosts using Dell® r610 servers with 16 cores and 48GB memory each. 2-Systems also integrated the new Dell Equalogic Storage Area Network that contains the workloads and documented the infrastructure. After this on the job training, Stoas Learning scaled the environment up to seven production hosts and a few hosts for test and preproduction.
“Citrix XenServer, Enterprise Edition offered the best value for the money: an easy graphical user interface, all the important features like XenMotion for live migration of servers to build a high availability environment. In addition, Dell supported XenServer on their hardware and storage,” added Rene Geling, system and network manager at Stoas Learning. “In 2009, we selected Citrix solutions as the preferred and strategic infrastructure for the virtualized future.”
The virtualized production environment now consists of 80 physical servers with more than 400 workloads. Ninety percent of the workloads are Windows® based and 10 percent run Linux.
Although Stoas Learning sometimes uses XenConvert to easily migrate existing machines to XenServer, the company often chooses to reinstall servers. This enables thin provisioning and saves a lot of storage on the SAN. “With Citrix XenServer, servers can boot from a golden image on the SAN and can run with or without a limited internal storage capacity,” continued Geling. “Speaking about the SAN, with XenCenter we are able to manage the virtualized environment in a user-friendly way, and the Dell Equalogic SAN integrates seamless with XenCenter thanks to StorageLink, a feature of Citrix XenServer, Enterprise Edition. We do not need to look at the separate storage management interface to manage the SAN. XenCenter is the one and only management console we use for day to day administration of the complete virtual infrastructure.”
As a result of the process to improve the quality of the environment, there is higher demand on the infrastructure such as improved service levels to customers, high availability and scalability. The system administrators at Stoas Learning now need to comply with these increased demands and manage more environments with additional advanced features. “Citrix XenServer created a well-organized virtual infrastructure that can easily be administered. We now manage a more advanced and high availability infrastructure for more customers than ever before, with the same IT staff,” Speeks said. “In addition, the application administrators who previously also had some system administration tasks now are freed from this burden and are able to spend 100 percent of their time on their own job. The complete system administration is now centralized and much more efficient.”
Stoas Learning now has a flexible solution for customers. When a customer with 100 students requests an upgrade for the environment to 1.000 students, this can be realized very fast. Instead of two weeks for ordering, delivery, installing and configuring servers, it is now possible to provide customers with the exact server they need within 30 minutes. Moving running production workloads with Citrix® XenMotion®, changing configurations and adding capacity is very easy using the Citrix XenServer management console XenCenter®. Although it is almost impossible to quantify cost savings because Stoas Learning upgraded firewalls, switches and other IT components as well, the additional advantages such as increased availability, increased security and better performance speak for themselves. “We plan to build a redundant twin datacenter, one internal and one external, to increase availability even more,” said Speeks. “The first virtual XenServer hosts are already running in the new datacenter outside our network. The flexibility of a virtualized infrastructure helps us in moving workloads to the external location.”
Stoas Learning plans to implement load balancing and application acceleration for the web-based environment Questionmark Perception, the e-exam environment for schools. Because of the perfect integration with XenServer and XenCenter, Stoas Learning is currently doing a proof of concept with the Citrix® NetScaler® VPX load balancer, a virtual appliance running as workload on XenServer. NetScaler VPX will enable peak loads to be balanced to multiple web servers on otherwise lightly used servers on exam days.
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