When a public school district launched its first Internet-accessible student information server for staff and parents,...
the IT department had to deploy enterprise-class hardware load balancers for the first time. The challenge was finding easy-to-use load balancers that were affordable and had the right feature set.
"Cost was a pretty large factor for us," said Benjamin Wilson, technology operations manager for Springfield Public Schools in Massachusetts. "We were also looking for ease of management. And the third thing was that we wanted to get as much out of the load balancers as we could. We needed to know how we were going to leverage them for other things in the future. So we were looking for something that could power more than just our student information system."
The hardware load balancer selection process started with Springfield's software vendor, Pearson School Systems, which sells the PowerSchool student information server application. Pearson recommended three hardware load balancer vendors to Wilson: F5 Networks, Cisco Systems and Kemp Technologies. Wilson narrowed the choice down to F5 and Kemp, which both had load balancers within his price range.
Then began the comparison. F5's lowest-end application delivery controller, the BIG-IP 1600 Series Local Traffic Manager, was rated for a maximum of 5,000 SSL transactions per second with 1 Gbps throughput. Kemp's comparably priced product, the LoadMaster 5500, offered 10,000 SSL transactions per second. F5's next class of hardware, the 3600 Series, offered the specs Wilson needed, but it was out of his price range. More than 2,500 teachers and the parents of 25,000 students would be using the PowerSchool application, so Wilson needed a box that could handle 10,000 transactions per second.
"It really came down to connections per second for SSL connections," he said.
Wilson deployed two Kemp LoadMasters in a multi-homed, active-passive configuration. The hardware load balancers sit in front of 15 servers that are running the PowerSchool student information server.
"There's a virtual address and the virtual address is always on the active node," he said. "When you're within the load balancer interface on the virtual address, you can see all the servers behind it. You can create pools of server resources. PowerSchool is broken into different parts, with teacher access and other things. So you can go into the LoadMaster and see the servers and see what's up and down. And if you want to add another server into the pool it's as simple as clicking the add button and typing the additional IP address of the server."
So far the Kemp hardware load balancers haven't had any problems during their first year or so in production. During a recent data center relocation, a mishap with documentation led to the Kemp boxes being cabled backwards.
"We cabled them backwards, but the secondary node just picked it up and it just worked," he said.
Wilson is adding six servers to the student information server pool soon, and he expects that process to go well. The two load balancers also have the capacity to work with several other applications that he is launching for the school system.
"We have [a Microsoft Office SharePoint] farm behind it, which is in evaluation mode and about to move into production," Wilson said. "We are also putting a Stoneware [Remote Desktop Application] cloud behind it. That's coming out in February. The final thing we're looking at is putting [Microsoft] Exchange behind it."
"For the most part we have pretty basic needs, even though we're a large school district," he said. "The need is simply for scalability. We want to be able to take a rule and just keep cloning that and throwing that behind the load balancer. We're not doing something fancy here. I'm sure there are some companies that would look at certain features that only an F5 or Cisco solution would provide, but for our needs, there was nothing more that we needed that the Kemp solution couldn’t provide."
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