ARISTA NETWORKS - STORAGE STRATEGY

at-a-glance

Data Center Class

A Rational Storage Strategy

To Unify or Not to Unify?

Arista Networks views storage networking as a key technology in the data center and a key area of focus because of the architectural disruption that has started, but is far from finished.

Many incumbent networking vendors are touting FCoE as a panacea technology - the silver bullet answer to all storage challenges. Reality is far different from the hype.

Arista’s goal in storage networking is to support the broad market transitions that are happening in storage and support our customers storage interconnect requirements - be they block, file, IP, Ethernet, or FibreChannel.

Mature TechnologiesThere are several mature solutions for storage interconnect available:

Network Attached StorageNAS is a common form of file based storage transfer. Arista switches are commonly deployed with NAS offered from companies such as NetApp. With 10GbE and a low-latency network fabric NAS has become the medium of choice for connecting VM farms and many storage sub-systems of high performance capability systems.

iSCSIiSCSI is growing rapidly in popularity, it offers an end-to-end unified fabric capability today, works on most existing network infrastructures, and most importantly scales very well because it can traverse a router-boundary. Latency, especially in a lossey environment is an ongoing concern some raise. Arista,

INSIDE

HOW UNIFIED IS UNIFIED FABRICthe hype cycle of FCoE has far surpassed the ability to use it in effective network architectures

WHYThe primary value of FCoE is in host cable consolidation. The primary value to its strongest network proponents is in vendor lock-in and margin creation.

WHO CARESStorage and Network administrators grappling with the challenge and question of if and when to consolidate their storage and Ethernet networks together and build a ‘Unified Fabric’

WHAT IS NEXTToday’s FCoE implementations are clearly first-generation technology with little economic incentive in their deployment to the end-users.

Choose your storage networking strategy first, decide what metrics make sense for your business, then see how vendors products fit your architecture

ARISTA NETWORKS - STORAGE STRATEGY

offering low-latency and lossless transmission enables very scalable iSCSI deployments.

FibreChannelFibreChannel is here to stay, regardless of what some vendors claim. Arista plans to interoperate with a variety of FibreChannel gateway offerings, both FCoE and FCIP. FibreChannel excels at high transaction volume architectures, especially where symmetric replication is required over a metropolitan area network. As future silicon technologies are developed some are targeting ‘dual mode’ ports that may be either Ethernet or FibreChannel enabling a true freedom of choice.

So where is FCoE?

Nascent TechnologiesFibreChannel over EthernetFCoE is in its infancy, although is promising at maturation. FCoE today is far more vendor-push than customer-pull, as evidenced by low volumes of FCoE Converged Network Adapters being shipped versus some vendors claims of switching volume.

Today’s FCoE architectures shift the point of protocol divergence from the server to the top-of-rack switch. The number of horizontal cables needed from rack to aggregation does not change, yet now you introduce yet another data-link and Ethertype. The size of the FibreChannel network to be supported is only marginally reduced, and is often limited in I/O performance.

Based on current product availability customers trade off scalable network designs, stable L3 routed architectures, performance, latency, and most importantly supplier diversity in making an early move to FCoE.

Will Arista build FCoE Switches?This is a matter of definition. The Arista 10GbE switches have hardware support for the IEEE DCB specification that enables lossless Ethernet (IEEE 802.1Qbb Priority Flow Control). In order to synchronize the IEEE 802.1p CoS bit selection Arista is also adding software support for Data Center Bridging Exchange, IEEE 802.1Qaz). This will allow an Ethernet attached storage

TODAY’S FCOE DESIGNVENDOR X’S ‘BEST PRACTICE’

OPTIMUM FCOE DESIGNWHAT ARISTA IS BUILDING TOWARDS

FCoE Switch FC Director

Core LAN Switch

Fabric Switch

Cost Effective, Simple, ModernComplex, Power Hungry, Costly

Fabric Switch

ARISTA NETWORKS - STORAGE STRATEGY

system to negotiate lossless delivery of Ethernet on a specific QoS lane with the Arista 7100 Series providing 10Gb Ethernet access and the Arista 7500 Series aggregating Arista 7100s and providing the buffer capacity necessary to reduce and absorb congestion reducing the PAUSE frame rate. The Arista switches can carry FCoE frames, losslessly, from initiator to target with a single-switch architecture.

In order to support multi-hop FCoE, a desirable network architecture, Arista intends to support FIP, the FCoE Initialization Protocol, to discover and initialize FCoE capable devices.

Arista is focused on making FCoE real-world deployable, and working in concert with storage partners who will provide the FCoE to FC gateway function at the SAN edge, not the Ethernet rack switch. The gateway can be more cost effectively deployed and managed far more easily when interfacing between the storage targets and the lossless DCB LAN.

Why Arista for Storage Connectivity?

Storage is, at its heart, data. The more data that can be moved from host to target the more efficiently the host will process applications. Arista switches have proven to be the highest performance, and top rated 10Gb Ethernet switches available, winning the prestigious Network World

ClearChoice comparison of 10Gb switches in January 2010. The Arista 7500 won the Best of Interop Award in the Infrastructure category and the Overall Best of Interop Award in April 2010.

The lower the latency between a storage write and the acknowledgement from the storage target the more efficiently the host can process data and applications. Arista 10GbE switches are among the lowest latency available- ranging from 600ns for 24-ports to 1.2usec in the industry’s only 1RU 48-port 10GbE switch and 4.5usec at 384-port density with the Arista 7500 Series.

If the storage and host are connected at different speeds buffering is a very important consideration, for speed-shifts Arista has a line of switches with extremely large buffers, over 100x what other vendors deliver. This absorbs bursty reads/writes and does not drop frames reducing retransmissions, again improving efficiency and application performance.

Arista is committed to an open storage market - one that equally supports iSCSI, NAS, SAN, FC, and FCoE. Arista is partnering with top storage system providers such as EMC, Dell/EqualLogic, NetApp, and Panasas and top-tier NIC vendors such as QLogic and Emulex to ensure customer success in deploying these mission-critical applications.