Feature

The case for network smarts

Ezine

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Will NAS move to the
intelligent switch?
Data replication,

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backup, volume management--these are just some of the storage services slated to move into the network. But what about that most commonplace of storage services--file services, e.g., NFS and CIFS support?

These days, the mainstream approach to file services is network-attached storage (NAS) appliances and heads for file services, which will probably remain the case for the foreseeable future, says Jeff Hornung, vice president of marketing and business development at Spinnaker Networks, Pittsburgh, PA, a start-up offering NAS and NAS head products.

It's conceivable that over the next couple of years, NAS heads will come as add-on blades within an intelligent switch vendor's chassis, he says. That may provide benefits in terms of space savings, but introduces the downside of becoming locked into a switch vendors' platform for NAS capabilities. Later on, we could see tighter integration with intelligent switch platforms, but NAS, "as a file service, sits at a level above" blocks, and as such, wouldn't benefit much from port-level processing.

"When you think about moving intelligence into the network," Hornung says, "you only want to do what makes sense, that is, what brings a significant benefit to IT."

At least one major OEM agrees with Hornung's sentiments. "There are people that want to load these platforms with everything but the kitchen sink--here's an appliance that's a desert topping and a floor wax," says Scott Gready, director of virtualization, HP storage software group, in charge of HP's CASA line. But while "it'd be quite easy for us to load file services on," Gready says, "we just haven't seen a demand for it."

But that doesn't mean that there isn't a role for network-based services in the NAS world. Rainfinity, San Jose, CA, for example, sells a data migration appliance called RainStorage which allows NAS administrators to do the unthinkable: move data between NAS devices during the day, without disrupting end users, says Jack Norris, Rainfinity vice president of marketing. How does it work? The RainStorage appliance simply sits out-of-band on a VPN until an administrator initiates a data migration, at which point it moves in-band, managing copy functions, and transparently redirecting end-user file requests. When the data movement is done, RainStorage moves back out-of-band until the next time an administrator wants to migrate data.

Relief for backup
Copy services also open the door to better backup. Rather than bringing down an application in order to perform backup, you take a snapshot of it, which you can then use as the basis of your backups.

According to John Webster, senior analyst and founder of the Nashua, NH-based Data Mobility Group, the advent of network-based storage services could finally result in "the long-awaited, vaunted" serverless backup.

It could also mean substantially faster disk-to-disk backup. Virtual tape software vendor Alacritus, Pleasanton, CA, has ported its software, Securitus, to the Brocade SilkWorm Fabric Application Platform (SilkWorm Fabric AP), for an anticipated 3X boost in performance (from 500MB/s to 1.5GB/s) over running it on a PC, says Don Trimmer, Alacritus co-founder and chief strategic officer. HP recently demonstrated a 3TB/hr backup, "but they threw a couple million dollars in hardware at it," Trimmer says. In contrast, Alacritus expects to achieve 5TB/hr backup rates "with $150,000 worth of hardware."

Another big bonus is improved utilization. Conseco's Lucero, who pools 70TB across various EMC arrays, has seen utilization skyrocket since installing SANsymphony approximately a year ago. For example, by assigning three servers with a total of 3TB of capacity to SANsymphony, Lucero was able to "buy back" 1.3TB of captive capacity. At $.08/MB, Lucero figures he saved his company over $100,000 with that example alone.

Virtualization can also keep utilization rates high by automatically provisioning capacity to applications. SANsymphony, for example, can assign applications capacity in granular 128MB chunks as needed.

Appliance or switch?
If network intelligence is a consensus choice, the package it should be delivered in is not. Your options will revolve around the in-band PC appliance model, such as FalconStor's IPStor, DataCore's SANsymphony, as well as IBM's SVC and HP's CASA; and the out-of-band intelligent switch, as exemplified by Brocade's Silkworm Fabric AP, Cisco's MDS 9000, and Maxxan's MXV320--technology that's thus far unproven, but that has many proponents. Certainly, the appliance model has the longest track record and most traction in the marketplace, with many happy customers.

James Dyches, director of computer operations for IT distributor Bell MicroProducts, San Jose, CA, built a new data center in Montgomery, AL, two years ago around FalconStor's IPStor. Previously, the company's main data center was housed in San Jose, CA, "but we had no backup, no disaster recovery--no nothing." Working with FalconStor, Dyches built a new data center around an active/active pair of FalconStor servers virtualizing two Rorke Data Fibre Channel (FC) arrays with a total of about 500GB of data, largely e-mail and end-user files. The data is then replicated over ATM to the San Jose data center. How does he like it? "I couldn't be happier with my access times, I couldn't be happier with my uptime, I am completely contented," Dyches says.

At the same time, there are some users who aren't about to take the risk of putting those appliances in front of enterprise class arrays.

HP CASA user Mark Deck, director of infrastructure technology at National Medical Health Card Systems Inc. (NMHC), a pharmacy benefit manager in Port Washington, NY, is one of them. In addition to midrange SAN equipment, NMHC also owns an HP XP256 array. "As much as I'd love to" virtualize the xp256 with CASA, "it could be a bottleneck," he says. Instead, he'll wait for CASA to run on Brocade's SilkWorm Fabric AP, as promised by the two companies this March.

Why does he think the PC-based CASA would be a bottleneck? For one thing, all the hosts connected to NMHC's CASA box are Wintel boxes, and "they only run at half a gigabit." You can connect a lot of servers before you saturate your virtualization appliance. The same can't be said of NMHC's large HP-UX servers, though.

Similarly, Roy Singh, an independent consultant specializing in data center design and implementation, is all for the concept of network-based virtualization, but has reservations about the PC platform approach.

"Virtualization in a network environment would make EMC and HDS [arrays] look more homogeneous, which would make my life much easier," says Singh. But "performance is my thing," he says. For that, you need to "elevate [virtualization] to another level, closer to the port."

In contrast to virtualization engines running on PCs, intelligent switch platforms are purpose-built devices with processors at every port. And whereas existing virtualization engines run in-the-data path or "in-band," intelligent switch platforms also offload some processing onto an out-of-band control path.

This was first published in June 2003

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