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Faced with rising server configuration costs, the City of Westminster, Colo., chose DH2i containerization software to save money while clustering its more than 30 SQL Server systems.
Westminster began using DH2i containerization software, DxEnterprise, after a change in Microsoft's licensing policy made its previous server configuration too expensive. Before beginning work with DH2i, the policy in Westminster was to create a standalone server for every application, and the creator of that server was responsible for it. This meant that each server was maintained in a different manner, and backups were not stored in a consistent place. By the time Westminster started looking for a way to cluster its servers, it had over 30 separate ones running SQL Server. When Microsoft changed its volume licensing policy, all those servers rapidly became a major expense.
Westminster chooses clustering
"We'd been talking about clustering for years," said Art Rea, the city's software engineering manager. "It's not something that just came up."
Rea first heard about DH2i in a user group for local municipalities in Colorado. He discussed SQL Server clustering software and DH2i with another local city and looked into it, as well as other options. However, the other clustering software options all would have forced Westminster to upgrade its SQL Server licenses from standard to enterprise edition, and they would have had to buy the enterprise edition separately for each of those servers, making the cost prohibitive.
After looking at the options, the City of Westminster chose DH2i containerization software. With containerization, an application is encapsulated in a container with its own operating environment. It's used as an alternative to full virtualization and allows for the separation of application instances and infrastructure. Instances can move transparently between hosts. Containerization software helps with consolidation, high availability and disaster recovery.
Denny Cherry, principal consultant for Denny Cherry and Associates Consulting, explained that DxEnterprise circumvents the restrictions Microsoft puts on the number of nodes allowed in a cluster for standard edition users. Normally, standard edition users can't have more than two nodes in a cluster, but, since containerization separates the instances and the server, SQL Server doesn't know that it needs to enforce that rule on larger clusters. This allows the user to continue using standard edition while clustering, which saves them a considerable amount of money.
Larry Garlicklead software engineer
Although, according to lead software engineer Carmen Zukas, "cost was a major thing," it wasn't the only consideration the cluster team had to work with. The City of Westminster uses SQL Server versions 2008 R2, 2012 and 2012 R2 and, Zukas explained, it needs all of those versions for the city's upgrading process and because the city uses third-party applications that require SQL Server versions supported by those applications. Microsoft doesn't allow clustering between versions of SQL Server, which would have severely limited clustering options if they had chosen to use Microsoft's clustering software.
However, lead software engineer Larry Garlick said, "DH2i's product allows us to have that -- we can have 8 and 12 and all that sitting out there. DH2i gave us the ability to mix and match."
Also, before adopting DxEnterprise, Westminster's SQL Servers didn't have built-in redundancy or capacity to failover to a new server because each of the servers was configured separately. In the past, when a server went down, all anyone could do was try to get it up and running again as fast as possible. Downtime with DxEnterprise is, according to Zukas, "stop and start. Maybe eight times out of ten the end user will never even know it happened."
Rea added, "We run 24/7 on almost all of our applications. Redundancy built into our systems is important."
Rea explained that redundancy and high availability are especially important in this situation because the servers are used to run critical systems for the city. The servers support police, fire, the court system, finance and human resources, the geographic information system, public works and utilities, and asset management. For instance, the servers host the applications in charge of road maintenance and regulating which utilities can lay cables across streets and how much it should cost them. Another server contains the infrastructure for managing the city's water and waste water, something highly regulated by the federal government. Fees and jail terms are also managed through these servers.
The process of consolidation
The cluster team started with DxEnterprise in a proof-of-concept environment and progressed from there to production. They worked with DH2i on the original setup. David Cotton, IT systems supervisor, said that although some of the specific requirements for DH2i were a challenge, once he understood the way the procedure worked, everything began moving smoothly. He added that DH2i also provided very helpful support.
Garlick said, "Each database we brought into the system brought its own challenges. There was a definite learning curve there."
Because each of Westminster's servers is set up differently, the addition of each of the servers had different problems to solve. Garlick explained that most of the issues revolved around finding out what login was running what service or what permissions were attached to what databases. The cluster team has been adding both new and old databases to the cluster. Rea explained that they were having no difficulties with the new databases.
The cluster team is taking a very slow, measured approach to consolidating their databases. Currently, they have nine databases consolidated out of 30, and 2 of those 9 are new databases. Zukas explained that they started with smaller databases with applications used only by the IT staff. They haven't gotten to the bigger applications like JD Edwards yet.
"We have to be methodological so that [users] don't notice any difference," Rea said.
Garlick explained that the plan was to consolidate everything over the course of the next two years and add new databases when it's time to upgrade them.
Right now, the cluster team is working on standardizing the location of the databases and establishing a standard place for database backups. "This is the first step in unifying it," Rea said. "We're able to deal with each database the same way."
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