Wednesday, October 18, 2017

Micro data centre architectures could fall victim to edge network latency

Links between micro data centres will need to be made using “public” WAN connections and with enough bandwidth for the applications they support.

Large micro data centre deployments could be hindered by the “unknown” impact of network latency in their operations, a Schneider Electric whitepaper has revealed.

The “major unknown”, also seen as a “risk” by the authors, could jeopardise the future data centre architectures if the industry fails to bring down the costs associated with the networking technology used for such edge computing deployments.

“One major unknown, and risk, for this future data centre architecture is the effect of network latency on the distributed micro data centres,” said Victor Avelar, Director and Senior Research Analyst at Schneider Electric’s Data Center Science Center, in the “Cost Benefit Analysis of Edge Micro Data Center Deployments” whitepaper.

“Google uses dedicated “non-public” fibre links between its data centres to allow data flow between them. This is cost prohibitive for typical companies, therefore, the links between micro data centres will need to be made using “public” WAN connections and with enough bandwidth for the applications they support.”

However, despite this hurdle, the whitepaper highlights the applicability of micro data centres at the edge of the network and their benefits from capital expenditure to speed of deployment.

Scalability, speed of deployment, reliability, and outsourcing to the cloud and colocation facilities are the four main drivers highlighted in the paper.


Capital costs still prove benefits of edge

Capital costs advantages are also behind the rapid growth of the micro data centre.

Avelar said: “The biggest capital expense advantage that micro data centres have over building a traditional centralized data centre, is that they can typically run off of a building’s existing physical infrastructure.

“In many cases, existing buildings have spare power capacity to support a micro data centre both from utility and emergency generator power. In other words, micro data centres can utilise the “sunk costs” in facility power (e.g. switchgear), cooling (e.g. chillers), and core and shell construction, making it less capital intensive than building a new data centre.”

Schneider Electric has carried out a capital cost analysis of a data centre architecture deployed with micro data centres, and compared it to a traditional centralised data centre.

Avelar explained: “For the centralised traditional data centre, we used the data centre cost value shown in the results section of the tool. We compared this traditional data centre to 200 micro data centres (single rack 5 kW/rack) distributed throughout various buildings. Note that this does not mean you would need 200 buildings since more than one micro data centre could be housed in a single building.

“The micro data centre capital cost was estimated based on micro data centres available on the market today. For the micro data centre, we eliminate the capital cost (materials, labour, and design) of the subsystems that are typically present in buildings (sunk cost). These subsystems included core & shell, raised floor, switchgear, and generator.”

In the end, the company concluded that the capital expense for building a single centralised data centre rated for 1MW of IT load is $6.98m or $6.98/watt. The capital expense of 200 5kW micro data centres is $4.05m or $4.05/watt.

“Micro data centres represent a 42% savings over a centralised data centre,” said Avelar. “Note that if fire suppression was removed from traditional and micro data centres the overall savings would increase to 48% savings.”

He concluded: “The benefits of distributing micro data centres are that they scale as needed, reduce computing latency, and reduce the risk of bringing down the entire data centre operation (i.e. reduce single points of failure).

“Similar to a distributed IT architecture, if more capacity is needed in the future, another micro data centre is added. Standardising these micro data centres results in further benefits including reduced deployment time, simplified management, and lower maintenance and capital costs.”