But will users buy in?
By Dave Simpson
Although it's unclear when—or if—the trend toward fabric-based intelligence (running storage applications on switches) will take off, it's clear that there is considerable end-user interest in the concept. In an InfoStor reader survey, 44% of the respondents said they would prefer to run storage applications on switches, while 33% preferred running applications from disk arrays and 23% chose host servers (see pie charts).
Interest in fabric-based applications was spurred by recent announcements from some large vendors. For example, late last year IBM delivered fabric-based virtualization and storage services by porting its TotalStorage SAN Volume Controller (SVC) software to Cisco's MDS 9000 switches and directors (see "IBM, Cisco team on virtualization," December 2003, p. 1). At about the same time, Veritas announced it had ported its Volume Manager (VM) software and related applications to Cisco's MDS 9000 switches. Veritas' VM has the lion's share of the host-based volume management software market.
IBM and Veritas have implemented their code on Cisco's fabric switches in different ways. For example, IBM's SVC software runs on Cisco's Caching Services Module (CSM), a specialized line card that plugs into MDS 9216 switches or 9500 series directors. Veritas' software—dubbed Veritas Storage Foundation for Networks—runs on Cisco's Advanced Service Module (ASM) and operates through Fibre Channel ports, providing port-level processing. In both cases, the goal is the same: to provide centralized storage services and—potentially—cost savings to users.
Another difference between the IBM and Veritas approaches is that, at least for now, IBM's software works only with IBM disk arrays (although the company promises support for other vendors' arrays), while Veritas' software works in heterogeneous array environments. Veritas has tested the software with arrays from EMC, IBM (Enterprise Storage Server, or "Shark" arrays), and Hitachi Data Systems (as well as HDS arrays from resellers Hewlett-Packard and Sun), according to Arya Barirani, director of strategic partner marketing at Veritas. Barirani claims one more potential advantage over IBM and other vendors that may port their software to fabric switches: "Veritas is the leader in volume management."
Proponents argue that advantages of fabric-based applications (versus host- and/or array-based applications) include consolidated/centralized (vs. distributed) management, cost savings (mostly in ongoing management costs, not necessarily up-front costs), easier support for heterogeneous (server and storage subsystem) environments, simplified provisioning, improved resource utilization, and improved availability (because servers are insulated from storage application changes).
But analysts note that, although fabric-based intelligence makes sense on paper, it's still unproven technology that's in the fledgling stages.
"The potential value proposition [of fabric-based intelligence] is all based on solving storage 'sprawl' and centralizing management," says Marc Staimer, president of Dragon Slayer Consulting. "The key will be how seamlessly vendors make their solutions work with current and future storage environments and how much real value they provide. In spite of the hype, there is no guarantee of success regardless of vendor name."
"Fabric-based intelligence is fundamentally a good thing, but it's not a slam dunk, in part because of inertia. SAN [storage area network] users already have solid solutions with host-based or array-based applications and they've already gone through the pain of implementation," says Arun Taneja, founder and consulting analyst with The Taneja Group. "However, many users may consider fabric-based applications for next-generation SAN implementations."
As evidence of how difficult it is for vendors to port applications to new platforms such as fabric switches, the deal between Veritas and Cisco was originally announced in mid-2002. And delivery of IBM's SVC on Cisco's switches was in the works for two years, according to IBM officials.
In addition to Volume Manager, the Veritas Storage Foundation for Networks software includes point-in-time snapshot capability, online re-layout, dynamic multi-pathing, provisioning, and storage virtualization. (IBM's SVC on Cisco switches provides similar software functionality.) Users can optionally integrate Storage Foundation for Networks software with Veritas' SANPoint Control management software (in which case SANPoint Control would still run on SAN-attached hosts, not on the Cisco switches).
One of the expectations for fabric-based intelligence is that it will be less expensive than host- or array-based software implementations. Veritas' Storage Foundation for Networks comes in two versions. The base-level "standard" version includes only the core VM functions and is priced from $12,000 for a 16-port (disk array or host bus adapter ports) license. Veritas did not provide pricing for an "enterprise" version of the software suite that includes VM plus all the other applications.
Because pricing on host-based software varies so widely and depends on many factors, users are left to make price comparisons based on their specific situations. As for Veritas, company officials seem to dodge the question of whether fabric-based applications will be less expensive than host-based applications: "That's an apples-to-oranges comparison," says Veritas' Barirani. "Although users can consolidate functionality on switches, many will retain some host presence for key applications."
On the cost front, analysts say that it may come down to performance and ease-of-management issues rather than direct price comparisons. "Even if the initial price is the same, fabric-based applications will provide better performance and should provide easier or better management," says Taneja.
Unlike the IBM-Cisco partnership, where IBM resells Cisco switches bundled with its SVC software, Veritas and Cisco will stick to their core competencies: Veritas will sell the software and Cisco will sell the hardware. So far, Veritas has signed two services partners: Forsythe Solutions Group and Stack Computer.
For more information about fabric-based intelligence, see the following articles that have appeared in InfoStor:
"Maranti touts 'application-aware controllers,' " p. 8, in this issue
"Cloverleaf targets large SAN/NAS shops," p. 8, in this issue
"IBM, Cisco team on virtualization," December 2003, p. 1
"McData squares off against Brocade, Cisco," October 2003, p. 12
"StoreAge touts snapshot capabilities," October 2003, p. 12
"Vendors move toward fabric-based intelligence," June 2003, p. 1
"IBM begins virtualization rollout," May 2003, p. 1
"Fabric-based intelligence gets vendor nod," April 2003, p. 8