Pay-as-you-go mobile phone users may not realise it, but financial services company Paypoint uses Stratus' fault tolerant servers to keep their phones topped up.

Paypoint describes itself as "a payment collection network used primarily for cash payments of bills and services and prepayments for mobile telephones and energy meters. The company has a growing network of payment terminals located in newsagents, convenience stores, petrol stations, and some supermarkets all over the United Kingdom."

It's also a user of Stratus' fault-tolerant servers -- but it didn't star out that way. Founded originally for offline payments, according to IT operations manager Mike Holden, in 2000, Paypoint won a contract from its first mobile operator, Vodafone, to manage its top-up mobile phone service.

In IT terms, this meant it needed to institute a process of authorisation in real time. As marketing manager Peter Binns put it: "Around-the-clock availability became the top priority for PayPoint because the systems supporting the payments were now not only critical to the company itself, but also to its customers. These customers also generate huge transaction volumes so any delays would create a significant build-up for our operations.”

The infrastructure Paypoint chose was a cluster of servers with the capacity to support real-time transaction processing running Postilion, payment processing software from Mosaic. According to Holden, the company chose a cluster because of its resilience. There are two sites, each with two servers with one in hot and the ptehr in standby mode. The two sites are also mirrored.

The problem Paypoint found was that the system was extremely high maintenance and complex to manage. "We had two nodes at each of two sites, and all changes and patches had to be made on both. It was twice the workload, in addition to which the failover configuration was complex to get set up and working", said Holden.

Holden had no issues with the resilience of the system, though: "We had to use that failover facility and it worked fine from that point of view."

"Then Mosaic introduced us to Stratus, as the company had worked with the server vendor previously", said Holden. "I had also experienced them when working previously with other companies, so I knew their advantages. The result was that we decommissioned our clustered servers, wrote off the cost, and bought our first ftServer in September 2002."

"In the last three years", said Holden, "We've been happy with the system, having upgraded it further in 2003 by adding a second pair of servers. The result is that we can provide more services on two sets of three ftServers. Each set has a live, a standby and a test server and, as before, we retain a pair of mirrored sites for disaster recovery and resilience purposes. The company owns three W Series 4200 and three 5240 ftServers.

For Paypoint, the payback on its investment includes improved ease of management. "They're a lot easier to manage and maintain because you only need to manage one server per site. Also, there's less complexity in the architecture because there's no failover -- it's built into the server itself", said Holden. "This means there's no failover configuration to manage. It also works on a Windows platform so there are no added costs in terms of the skills base.

"In terms of management, the ROI means we've saved money. We've had application software issues but no hardware related issues, such as an installation or upgrade that hasn't worked."