The road to a converged data center fabric

Enterprises stand to save considerably by simplifying their IT infrastructure with CNAs on the server, FCoE switches in the network and FCoE on the storage array. By Akhtar Pasha

Most data centers in the enterprise segment tend to go with Ethernet for LAN and Fiber Channel (FC) for the SAN. Some CIOs in BFSI, telecom and manufacturing have started to explore the option of converging disparate networks onto Fiber Channel over Ethernet (FCoE), which is a lossless 10 GbE technology.

“The rising cost and complexity of building and operating modern data centers has led us to continually seek new ways to make a data center simpler and more efficient. While the cost of data center networking gear is relatively small in relation to the cost of server hardware and software applications, the underlying network fabric is the nuts and bolts infrastructure that connects all mission-critical resources. Therefore, a streamlined data center fabric enabled by using a FCoE switch can result in greater efficiency, productivity and lower the operating costs. We are evaluating this option,” said Daya Prakash Head - IT, LG Electronics India (LGEIL).

Despite the slowdown, LGEIL grew by 20% YoY and Prakash had to expand the IT footprint from one to three data centers thanks to the increasing load on the older data center as more applications were added and the company had to support more users than it had in the past. This created complexities in managing cables and the growing number of network devices didn’t help either. “FCoE would help us significantly reduce our data center costs. It gives us the chance to replicate our production site (primary site) to the DR site in Pune without compromising on performance, reliability and scalability, which was not possible with a dedicated FC link because of the high costs involved. Additionally, we do not have to manage multiple cables, switches, FC Host Bus Adapters (HBA) and Network Interface Cards (NICs).”

LGEIL would like to test FCoE on the server and storage side first and address the challenges and issues that it faces before it rolls out the technology for DR.

Tarun Pandey, Vice President-IT, Aditya Birla Financial Services Group, said, “In our existing data center, we are faced with the challenge of managing two different types of networks (FC SAN and Ethernet LAN traffic) with multiple cables, devices, adapters and switches. Therefore, we are open to a discussion in order to formulate a strategy for deploying FCoE.” As the company added applications and went in for server virtualization, it would eventually add new servers and storage that are FCoE capable. It is already using NetApp's V Series storage that supports FCoE.

Raghavan K., Principal Technical Consultant, Cisco India said that the vendor was involved in six to eight projects where customers were deploying FCoE and said that they were in various stages of implementation. He said that a bank had deployed FCoE in its existing data center. Since this bank has about 600-700 servers, maintaining separate cables for Ethernet and Fiber Channel was becoming difficult. Additionally, when it faced the challenge of moving its servers from one location to another within the data center, moving the cables along with the servers became a difficult task. Earlier, the bank was using an end-of-row switching architecture. By deploying FCoE, it earned a 60% reduction in its cabling costs. Two NIC cards with four Ethernet ports and FC HBA with two FC ports per server were replaced with a Converged Network Adapter (CNA) thereby resulting in 15-20% power savings per box.

Raghavan said, “Looking at the traction in large enterprises, in the next 18-24 months, FCoE will become a commodity.”

A former CIO of a large IT/ITES company who has moved to another global role said that if a CIO is setting up a new data center from the ground up, then he would like to evaluate FCoE as the cost savings from the cabling alone (in addition to lesser devices to invest and manage), would justify the investment. However, he felt that it was unlikely that a CIO would like to redo the wiring of his existing data center to accommodate FCoE. His feeling was that the technology would catch on in India after three-four years.

Surajit Sen, Director-Marketing & Alliances, NetApp, said, “CIOs are excited about the simple fact that the network infrastructure in a data center can be converged and that the RoI is quite compelling.” Inside the data center, the storage group owns and operates the FC SAN while the networking group owns and operates the Ethernet LAN. Hierarchical, political, and behavioral concerns in the data center and provisioning paradigms can present obstacles to CIOs when it comes to FCoE adoption.

LAN-SAN convergence

The legacy approach of deploying multiple networks, switching domains and tiers to handle a dizzying array of technologies has increased complexity, compromised performance and prohibited scalability in data center networks. Disparate network infrastructures currently exist for HPC clusters, LANs and SANs. Multiple oversubscribed switching layers are now in place to meet density and performance requirements as well as to contain costs. Adding to this complexity, each layer often uses a different operating system.

Subram Natarajan, Director, Systems Solutions Center, Executive IT Consultant, STG, IBM India, explained, “The move towards FCoE is inevitable as large customers have multiple networks with a mix of Ethernet, SAN and iSCSI and they are looking at increasing operational efficiency. The implementation of FCoE will be driven by the existing complexity of managing a large number of devices and the need to reduce the footprint of cables, adapters and switches.”

No matter what happens on the technology front, Ethernet is the future of networking because it is ubiquitous with virtually no replacement on the horizon. Additionally, the technology has consistently evolved in terms of performance and 10 GbE is poised as the next wave and is ready for rapid adoption. 10 GbE has numerous protocol improvements, the most significant being a lossless capability meaning that it doesn't lose frames at high utilization rates.

According to Sandeep Gosain, IT Consultant and former CTO of Panacea Biotec, CIOs should care about FCoE since improved protocols such as 10 GbE allow the use of a converged network for SAN and LAN connectivity which result in a less expensive set-up, centralized network management and more flexible provisioning of data center resources. This would let servers use a single Ethernet card for all communications. Clearly a converged network brings substantial benefits to IT organizations and the CIO community believes that 10 GbE will be the backbone of a converged network strategy, even though this is likely to happen over a two to three year period.

Raghavan explained that six to eight cables are typically attached to a server in an existing data center. Of these, four to six would be Ethernet cables and two would be Fiber Channel. Each rack would typically house four to eight servers. There would be 30-50 servers in a data center. Managing 64 cables per rack is a huge problem. Further, you need to account for the six NICs and two HBAs that also have to be managed, which further complicates matters and increases the cost of power and cooling. The NICs and HBAs can be replaced with a CNA which would not tax server resources as the processing is done by the CNA. So there is a clear saving in cabling costs, number of devices and power and cooling costs.

Using a single Ethernet network fabric from server to switch to storage, removes the requirement for a dedicated storage network and reduces the number of server adapters, cables, and switches required to support data center applications.

Window of opportunity

Perhaps a bigger factor than merely combining the networking and storage networking fabrics is to replicate data from a primary site to the secondary using FCoE.

Natarajan explained, “FCoE opens up a new frontier for SMBs. Earlier SMBs were wary of replicating their primary site at the DR site as it required a dedicated FC network at a prohibitive cost. Using FCoE, they can do the same as it uses IP-based communication. SMBs are looking for cost-effective ways to construct their business continuity and disaster recovery plans and FCoE would a big factor here in the next two years.”

Sanjay Jotshi, Director-Enterprise, India & SAARC, Juniper Networks India, had a different viewpoint. He said “There is no pressing need for FCoE today and we do not expect immediate, widespread deployment of I/O consolidation using this technology. However, a few early adopters might pilot some type of FCoE implementation in an effort to become familiar with the technology. Most businesses will likely wait until the economic benefits of deployment are clear and compelling.” He admitted that enterprise with complex data centers where FC HBAs and the number of virtual machine instances are growing would be justified in looking into FCoE. In his opinion, FCoE would be embraced by service providers including those providing cloud-based services rather than large enterprises.

Timeframe for deployment

While the appeal of a single network pipe is compelling from a cost and simplicity perspective, the transition from today’s network silos to a unified network would take two years or more.

Prakash and Pandey clearly pointed out that they would be using CNAs in servers to converge separate Ethernet and SAN cards to build small converged networks in pilots. The impact would be to demonstrate the viability of reducing connectivity and management complexity coming out of the server into the top-of-rack switch, which will still have distinct connections to SAN and Ethernet switches. After getting to grips with the technology they would then move on to the network level.

Prakash Krishnamoorthy, Business Manager-Storage Works Division, HP India, said, “Deployment would happen in a logical way with enterprises opting to deploy FCoE in non-critical areas, which would not impact their business. Only after seeing the cost realization and achieving a degree of confidence would they move on to the network. We are expecting the first few storage arrays supporting FCoE to be deployed in the current year but achieving critical mass would take three to five years.” HP India is currently doing three to four Proof of Concepts (PoC) using FCoE for its customers in India who are setting up new data centers.Initially, HBAs and NICs in servers will be replaced with CNAs. Then the Ethernet and FC switches will give way to FCoE switches. Lastly, we will see CNAs on storage arrays as well.

Raghavan added that customers can make use of top-of-rack switching (using an Ethernet core switch) for deploying FCoE while setting up a new data center. Instead of drawing multiple cables to multiple switches in a top-of-rack switching architecture, businesses can use only two cables that can be drawn to 20-30 meters easily.

akhtar.pasha@expressindia.com