Gartner Rebuffs Cost Claims For Converged Data Centres

The concept that multiple data centre networks can be made more efficient by converging them into one system using Data Centre Bridging (DCB) technology is flawed, according to analyst Gartner.

In a report issued this week, “Myth: A Single FCoE Data Center Network = Fewer Ports, Less Complexity and Lower Costs”, the analyst stated that converged data centre networks actually require more power and cooling and are more complex to manage than two well-designed separate networks.

“The industry is abuzz with the promise of a single converged network infrastructure, this time in the data centre core,” said Joe Skorupa, research vice president at Gartner. “Alternatively described as Fibre Channel over Ethernet (FCoE), Data Centre Ethernet (DCE), or more precisely, Data Centre Bridging (DCB), this latest set of developments hopes to succeed where InfiniBand failed in its bid to unify computing, networking and storage networks.”

Fewer networks don’t mean fewer switches

Skorupa added that the idea that a single converged data centre network would require fewer switches and ports wasn’t accurate “This is because as networks grow beyond the capacity of a single switch, ports must be dedicated to interconnecting switches. In large mesh networks, entire switches do nothing but connect switches to one another,” he explained. “As a result, a single converged network actually uses more ports than a separate local area network (LAN) and storage area network (SAN). Additionally, since more equipment is required, maintenance and support costs are unlikely to be reduced.”

The analyst added that DCB technology also introduces design and management issues. “When two networks are overlaid on a single infrastructure, complexity increases significantly. As traffic shares ports, line cards and inter-switch links, avoiding congestion (hot spots) becomes extremely difficult,” the analyst stated.

Emerging standards such as Transparent Interconnection of Lots of Links (TRILL) may make it easy to cut down on traffic hots-spots but it will take at least two or three years for the technology to mature, according to Skorupa.

Despite the barriers, there are clear benefits to standardising on a single technology for data centre networking and the process doesn’t have to mean combining or converging networks, the analyst said. “Settling on a single technology does not require that the networks be combined. Design, operations and troubleshooting is much easier with two separate networks, and it may also cost less to build two separate networks,” the analyst stated.

Converging data centre networks

Vendors championing the concept of converging data centre networks include Dell which announced new infrastructure management software and 10 Gigabit Ethernet connectivity to its server and storage offerings last December.

IBM also recently announced a partnership with Brocade’s family of enterprise IP/Ethernet switches and routers, extending an existing deal to sell Brocade’s storage networking products.

IBM’s partnership with Brocade follows Cisco’s entry into IBM’s home ground of servers, with the launch of its UCS data centre initiative. Cisco’s Unified Computing System strategy is designed to create a more integrated data centre solution that includes servers, networking, storage and software aspects. Some of these products come from Cisco, while others come from partners such as VMware, EMC and Intel.

Hewlett-Packard and Sun Microsystems have also made aggressive pushes into the space, and Oracle could become a factor following its £5 billion acquisition of Sun.