How much data?
How much data flows through the world's data centers, and what are the trends? This question has been addressed since 2011 by Cisco, with its annual Global Cloud Index (GCI). In its 2012 report, using network data from 10 enterprise and internet data centers, Cisco forecasts that global data center traffic will reach 554 exabytes (EB) per month by 2016, up from 146EB (1 exabyte = 1,000 petabytes = 1,000,000 terabytes). In annual terms, that's a rise from 1.8 zettabytes (ZB) in 2011 to 6.6ZB in 2016 — a CAGR of 31 percent:
Where does all this data come from? Cisco divides data center traffic (both business and consumer) into three broad classes: traffic that remains in the data center; traffic that flows between data centers; and traffic that flows from data centers to users over the internet or IP WAN. According to Cisco, the majority (76 percent) of traffic is the kind that remains within the data center:
When server workloads are considered, the momentum towards the cloud is clear, with Cisco estimating 180.6 million installed workloads in 2016, split 62/38 percent between cloud and traditional data centers, compared to 71.1 million workloads in 2011 with a 30/70 percent cloud/traditional split:
The average number of workloads per physical server in cloud data centers is expected to grow from 4.2 in 2011 to 8.5 in 2016; for the less efficiently utilised servers in traditional data centers, the estimated and predicted numbers are 1.5 in 2011 and 2 in 2016 respectively.
Cisco also predicts a 'changing of the guard' in terms of the regional distribution of cloud-based workloads: in 2011 North America led the way with 37.8 percent of 21.4m workloads, with Asia Pacific on 31.3 percent; in 2016 Asia Pacific is expected to host 36.2 percent of 112.1m workloads, with North America in second place on 26.4 percent.
What's clear is that, for the foreseeable future, organisations will be employing a mix of on-premise and outsourced IT infrastructure, with the major underlying trend being increased use of services located in public cloud data centers, particularly in the Asia Pacific region.