Are Switches the New Virtualization Platform?

Given the intrinsic truth in this observation, it may strike readers as quizzical that large array vendors now appear to be courting switch-makers and readily ceding some of their "secret sauce" functionality to them. The answer may have to do with the strategies of the array makers themselves .

In the case of EMC, a stated direction of the company for the past couple of years has been to pursue more aggressively a storage management software strategy. While the company has not backed away from its aggressive marketing of its own storage arrays, increased attention has been placed on its management software, which models itself on EMC's own array management philosophy and techniques.

For EMC, obtaining an early lead in storage area network management market by embedding its technology on the SAN switches of leading providers makes sense as a means of garnering greater market share. Competitor Veritas Software, a long-time advocate of host-based storage management and virtualization, is pursuing a similar course, based on statements made by CEO Gary Bloom at the Computer Measurement Group 's annual conference in Reno, Nevada, in December 2002. ^[7]

Are switch platforms the ideal location for LUN aggregation? Increasingly, the industry appears to be giving the strategy its approval. This may be fostered in part by the increasing presence of Cisco Systems in the SAN space.

Already a leader in IP network switching, Cisco was a major proponent of IP-based SANs and a force, together with IBM, in the development of the SCSI over Internet (iSCSI) standard within the Internet Engineering Task Force's IP Storage Working Group. The company had been evangelizing IP-based storage networks throughout 1999 and trash-talking everything Fibre Channel until a widely publicized announcement by the company that it would work together with the dominant Fibre Channel switch vendor, Brocade Communications Systems, to develop a protocol for using IP to stitch together isolated Fibre Channel fabrics (so-called "SAN islands") in mid-2000.

As previously discussed, the announcement raised more than a few eyebrows until it was understood that the two companies had been compelled by some of their larger customers (shared in common) to "play nice" with each other to fix the problem of SAN bridging. The Fibre Channel Over IP (FCIP) tunneling protocol was the outcome of the union, which dissolved with all of the acrimony of a Hollywood divorce in April 2002, amidst off-the-record claims by Cisco that Brocade was endeavoring to coopt the open standard to work only with its own switch gear.

Cisco's involvement with storage networking accelerated from there. By 2001, the vendor had become a fixture in the ANSI T11 Committee, which handles the development of standards for Fibre Channel, often criticizing standards proposals for their lack of completeness. ^[8] Often rebuffed in its efforts to steer Fibre Channel standards within T11, accused by pure Fibre Channel-focused vendors of being a thinly-veiled IP storage bigot and playing the role of a standards obfuscator, Cisco acquired its own Fibre Channel SAN switch company, Andiamo Systems, in August 2002, establishing itself squarely in both the IP and the Fibre Channel storage space.

In June 2003, the two companies ”Cisco and Andiamo ”introduced a draft Request for Comment (a preliminary standards draft in IETF parlance) to the IP Storage Working Group to develop nine management information bases (MIBs) for managing Fibre Channel fabrics. Within the document are MIBs for managing Fibre Channel SAN processes and elements that have never been defined, much less approved, by ANSI's T11 Committee as components of the organization's FC standards family. The apparent end run around ANSI was at least in part motivated by a desire to have Cisco's switch-based SAN fabric (as opposed to disk) virtualization method recognized by some standards group, according to prominent members of the IP Storage Working Group. ^[9]

Called VSAN, or Virtual SAN, Cisco's technology is intended to help designers build larger consolidated Fibre Channel fabrics with the same or greater security and application isolation than what is currently possible with conventional FC switch zoning. VSAN offers the ability to create separate virtual fabrics on top of the same redundant physical infrastructure, according to the vendor, but only if fabrics are created using switches that support the technology ”Cisco's own MDS 9000 Family of Multilayer directors and fabric switches, for now. ^[10]

With Cisco Systems becoming a more and more powerful force within the storage networking world, vendors with an eye on growing their market share in the storage virtualization software space are keen to do business with the networking giant. In April 2003, EMC and Cisco Systems jointly announced an agreement to work together to, among other things, create provide customers with intelligent switch technology for storage.

Not to be upstaged, Brocade Communications Systems has also been working to develop fatter switches through the integration of management software. In early 2002, the company was talking to analysts about its intentions to field a "V-switch" (a switch offering disk virtualization capabilities within the next 12 months). Whose technology would be integrated into the switch remained a mystery, given Brocade's partnerships with a wide range of virtualization technology vendors, including host software-based virtualization vendor, Veritas, in-band solution provider, DataCore, and out-of- band rival, StoreAge, until May 2003. At the Veritas Vision conference in Las Vegas, Nevada, the companies announced a co-development effort aimed at porting Veritas Volume Manager and Storage Resource Management software to the Brocade SilkWorm Fabric Application Platform (SilkWorm Fabric AP). A prototype of the solution was demonstrated at the show.