Case study: Virtualised storage adds value to Denmark's tunnel vision

State construction firm Femern selects DataCore system to help speed up Fehmarnbelt undersea odyssey and keep the sharks at bay

Large-scale, state-sponsored construction projects often run at a glacial pace, and the initiative to build a high-speed direct road and rail link between Denmark and Germany – known as the Fehmarnbelt Fixed Link – is no exception.

Connecting the German island of Fehmarn with the Danish island of Lolland was first mooted as far back as 2000, and it took a further seven years before the two countries’ transport ministers agreed to proceed with construction of the fixed link. Originally, it was going to be a 20km suspension bridge, and the construction was ratified by both parliaments in 2009.

But in 2010, it was announced the link would in fact be an immersed tube tunnel. Unlike traditional bored tunnels, immersion involves lowering prefabricated concrete sections of tunnel into a trench dredged across the seabed and then applying a protective coating several metres thick. At between 17km and 18km in length, the proposed tunnel would be five times longer than the current longest immersion tunnel, which forms part of the Øresund Link between Denmark and Sweden.

Once the start button is pressed, the project needs to run as quickly and smoothly as possible to avoid delays, escalating costs and negative headlines

Construction was supposed to start this year, but the revised plan still hasn’t cleared all the necessary legal and parliamentary hoops, although these are in the final stages and most observers expect development will finally begin in 2015.

Once the start button is pressed, the project needs to run as quickly and smoothly as possible to avoid delays, escalating costs and negative headlines. 

To support this, Femern, the Danish state-owned firm leading the project, has to ensure that up to 150 directly-employed engineering staff – as well as numerous contractors and consultants – can access all the necessary blueprints, specifications and workflow systems needed in a timely and efficient manner.  

But there was a problem. The company’s EqualLogic iSCSI storage array, accessed via its VMware-based virtualised environment, was prone to I/O bottlenecks and just wasn’t up to the job. 

Tim Olsson, Femern’s IT manager, says: “The EqualLogic array was at the end of its life and coming with an increasingly high price tag. We didn’t want to buy another one because it was too complex for our needs, with features we did not use, and it locked us into only buying disks from EqualLogic.”

Digging into software-based storage

After consulting with its IT partner Comm2IG, Femern decided to implement DataCore’s SANsymphony-V storage virtualisation software with Fusion-io PCIe server-based flash storage to boost performance for its critical applications. The project subsequently won an honourable mention at the VMworld Europe User Awards 2013.

The company implemented DataCore SANsymphony-V nodes on two HP DL380 G7 servers. Each server has two CPUs and 96GB of RAM, plus a 320GB Fusion-io PCIe ioDrive2 card. This gave Femern 50TB of storage capacity based on HP direct-attached storage in SAS and Sata drives.

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The system automatically examines the usage characteristics of any data being stored and migrates it to the most efficient and cost-effective type of storage (be that spinning disks or flash drives).

Because DataCore is a virtualised, software-only storage product, Femern can easily create shared storage using commodity or legacy arrays. 

“Now we can be more flexible in where we get our disks from,” says Olsson. “We can buy cheaper, slower disks or faster storage and make it available to our apps. It’s a seamless way of scaling capacity. So, for example, when our HP arrays reach end of life, it will be easy to migrate to something else.”

When work finally starts on the tunnel, Femern can now be confident that it won’t face I/O bottlenecks that slow workers down and rack up additional costs because of lost productivity. And given that the project will undoubtedly face ongoing public, political and media scrutiny, that’s critical.

Indeed, the project has already scored a few brownie points with the bean counters. Olsson estimates that Femern’s decision to opt for the DataCore/HP system cost it around £6,000, instead of the £35,000 or so it would have had to pay for a new EqualLogic array. So, for the time being at least, although the sharks may be circling he won’t have to bury his head in the sand.

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