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Cisco adds virtual machine awareness to Fibre Channel SAN switches

Cisco updates its NX-OS switch operating system to add new visibility to virtual servers communicating over the storage fabric.

Cisco Systems Inc. is making its Fibre Channel SAN switches aware of the virtual machines attached to them through joint development with VMware Inc.

"The virtual machine has become the atomic unit of the data center," said Rajeev Bhardwaj, director of product management. The update to Cisco's NX-OS switch operating system means that VMware ESX Servers connected through MDS 9000 fabric switches using NPIV can have separate logins and separate VSANs. ESX Servers can also be given access to multiple VSANs on an individual level, rather than being grouped by physical host.

The update to NX-OS allows quality of service according to virtual machine. The update also enables security attributes, such as authentication and access protocols, to follow the virtual machine if it's moved across networks using VMotion. Furthermore, storage administrators don't need to reconfigure or redesign the SAN fabric when moving virtual servers; they can create server pools consisting of virtual partitions of infrastructure offering different levels of service.

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Some of the new security features have been tailored to virtual machines, according to Bhardwaj. For example, zoning is enforced in hardware, so that physical ports are locked down and the same worldwide name can't be spoofed by an attacker accessing the SAN on a different port.

NX-OS can now report performance trending and monitoring statistics at the individual virtual machine level, indicating to administrators through Fabric Manager which virtual machines are using resources. Because virtual servers tend to be deployed in higher numbers than physical hosts, NX-OS has also been updated to support higher device counts, Bhardwaj said.

Virtualization succeeds despite infrastructure
"This is something you're going to see more of," said Zeus Kerravala, senior vice president of enterprise research with Yankee Group. The granularity addressed by Cisco with this product, he noted, has heretofore not been available for the infrastructure that supports VMware. "Virtualization has almost succeeded in spite of the rest of the infrastructure so far," he said. "It's like the Web. At first, things weren't optimized for it."

Integration between the network and compute fabric can impact the entire data center, Kerravala said. Other industry observers said that the promise of technology such as VMotion has yet to be realized because of rigidity in the underlying infrastructure. "In some ways, this is bigger than Cisco is giving it credit for," he said. "The first wave of virtualization has been a consolidation play, and it's fundamentally the same architecture [as before]. The full value of cloud-based computing [won't be] realized until there's a virtual machine optimized infrastructure."

Burton Group analyst Chris Wolf was less upbeat about the new features of NX-OS. According to Wolf, NPIV deployment remains problematic in large-scale environments. Generally, VMware is deployed using VMware's virtual file system, which allows multiple virtual machine files to share each LUN on the underlying disk system. NPIV dedicates a LUN to each guest.

Wolf called this a major obstacle to the kind of deployment that Cisco and VMware envision with this release in existing VMware shops. He said, "For an organization to take advantage of most of these features would require enormous financial investment to migrate and realign data on disks."

NPIV may limit virtual server mobility
Wolf also questioned whether this approach can boost mobility for virtual servers. "People in VMware circles make arguments that NPIV limits mobility, especially when specialized HBA hardware is needed," he said. According to VMware, the company's Raw Device Mapping can be run in Virtual Mode, which gives users who connect virtual machines to storage without the file system features such as snapshots.

Users who run application-quiescing agents inside guests for data protection also tend to assign one LUN per virtual machine. "But the perceived additional management overhead has kept many organizations from doing that," Wolf said.

Cisco looks to deals with VMware
Cisco is looking to its recent collaborations with VMware and its championing of the Fibre Channel over Ethernet (FCoE) standard for a boost in the storage networking market, where recent sales figures show it losing ground to rival Brocade. Cisco reported that its storage (SAN switching) revenue declined 4% year over year last week and lowered its guidance for the fourth calendar quarter of 2008.

Earlier this week, Brocade announced better-than-expected earnings for its fiscal fourth quarter, projecting $396 million to $400 million in revenue as opposed to prior guidance of $375 million to $385 million. That would come to about an 8% increase over last year.

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