SAN/NAS convergence: proceed with caution

Ezine

This article can also be found in the Premium Editorial Download "Storage magazine: Is it time for SAN/NAS convergence?."

Download it now to read this article plus other related content.

An eye on SCSI

    Requires Free Membership to View

    Login

After more than four years in development, it looks like iSCSI is shaping up to be an overnight success. The newly minted standard--which enables companies to run block-based data over standard IP networks--promises to dramatically lower the cost of entry for SAN deployments. By eliminating the need for pricey Fibre Channel (FC) gear and its related management costs, iSCSI-based SANs offer an attractive way to centralize storage without busting tight IT budgets.

The low cost of iSCSI SANs, combined with the ability to build scalable arrays of disks behind them, could tempt many medium-sized companies to test the SAN waters, says Jim Damoulakis of GlassHouse Technologies Inc., Framingham, MA. "The people who have been late to adopt or have not adopted SAN technology to any degree would be where iSCSI will make its inroads."

But while iSCSI SANs ship their data over familiar IP networks, they lack the file sharing facilities of NAS solutions. That's why Ron Lovell, of Greenwich Technology Partners, New York, NY, says that iSCSI SANs may make their biggest impact as a means to enable data access and backup over long distances. Freed of the 10-kilometer range imposed by FC connections, iSCSI SANs can support a true disaster-recovery environment, where remote backup and recovery can be performed over distances of hundreds of miles.

Jamie Gruener, senior analyst at the Yankee Group, expects iSCSI activity to pick up in the second half of 2003. But he believes more vendors must actively support the protocol with viable products before companies can contemplate a transition to IP-based SANs.

"iSCSI now lacks large vendor commitment to enable complete systems," Gruener says. "You can buy NetApp and Cisco, and Windows [Server] 2003 drivers, but you need more targets--storage arrays and systems that embrace iSCSI."

Greenwich Technology Partners' Lovell agrees, and says people that are enthusiastic about iSCSI SANs should be prepared for a wait. "If you look at the adoption for Fibre Channel back in 1996 to 1997, it really wasn't until five years later that people were adopting it for mission-critical systems."

"If you are a filer shop and you start having your filer do SANs, it's not like you can buy your switches and your host bus adapters from Network Appliance," says Preston. "A filer vendor in the SAN space won't have the traction to ensure interoperability."

In fact, Preston urges companies to carefully consider avoiding SAN deployments, if all they want to do is build a highly scalable file-based storage infrastructure. As an example, Preston tells of one large Fortune 500 company that was looking at deploying SAN solutions from EMC and HDS, and at the last minute, decided to bring NetApp into the picture as a third option.

"[NetApp] ended up doing very, very well in comparison to EMC and Hitachi, and their price was much less," says Preston. He adds: "If you are doing file, you should look at all the file options."

That's essentially what Buckeye Color Labs, a North Canton, OH-based photo service bureau, did, but with an interesting twist. It deployed FalconStor Software Inc.'s IPStor after a surge in storage demand strained its DAS. With the number of servers rapidly growing, the company turned to Cleveland-based consulting firm Chi Corporation to help deploy IPStor on a single Intel-based server running Linux.

IPStor's virtualization features allowed the company to reuse its existing disks, running them in a JBOD array from Chaparral Network Storage, Longmont, CO, alongside two new ATA disk arrays from Woodland Hills, CA-based Nexsan Technologies Inc. Most important, the solution allowed the company to access the disks via a direct SCSI attachment, sidestepping the significant costs of a FC array. Jeff Manuszak, senior engineer at Chi Corp., says the infrastructure can scale to 12TB before the number of required SCSI connections forces a switch to FC.

Getting virtual
Virtualization can also be a way to get around vendor lock-in. Both DataCore's SANsymphony and IPStor make it possible to unify block and file data access, while drawing disks together into a single, centrally managed pool of storage.

A new take on this approach comes from Maxxan Corp., San Jose, CA, which is just releasing its first-generation MXV320 intelligent switch for general availability as we go to press. Users can deploy blades on the switch (or in a standalone box) that run either FalconStor's IPStor virtualization server or Microsoft Windows Storage Server 2003 to provide file services on back-end SAN storage NAS vendor Z-Force, Santa Clara, CA, offers yet another spin on virtualization, selling file switches that link heterogeneous NAS devices to create a single, logical volume. The ZX-1000 switch sits between the NAS filers and the hosts and clients that access them to scale both performance and capacity. Company officials say that it could be made to work as a gateway, but it hasn't done that yet.

Unfinished business
Even as vendors tout the benefits of convergence, some storage consultants question the wisdom of such an approach. The Storage Group's Preston argues that the converged SAN-NAS product segment is more a product of vendor positioning than actual user need.

Says Preston: "I know of no one who said 'Gee, I wish my NetApp could do block.'" But he adds, "I do know NetApp and EMC salespeople who got tired of losing sales because of the other side's capabilities."

Jim Damoulakis, chief technology officer for GlassHouse Technologies Inc., Framingham, MA, says he has found interest in converged SAN-NAS solutions to be slim. "We have not seen a large number of examples of this," he says.

Take BMO Financial Group, which has left its direct-attached file-based storage in place while focusing on extending SAN operations. Brian Black, vice president of application management services at BMO Financial Group, says the bank operates a fast-growing, 50TB FC SAN that is built on HDS and IBM Shark arrays. Black says the bank has no immediate plans to transition its direct-attached file-based storage to the SAN. "The predominant strategy now is on new projects and getting them on to the SAN," Black says.

Northwestern University in Chicago places similar emphasis on its SAN operation. The university maintains a 10TB to 12TB IBM Shark-based SAN, which houses an Oracle database and various administrative applications. Another 5TB of file-based storage is contained on Dell PowerVault NAS boxes, which provide shared file access on the Ethernet network. Dana Nielsen, director of the data center and vice president of information technology at Northwestern University, says there are no plans to unify the NAS and SAN infrastructures.

Arun Taneja, president of consulting firm The Taneja Group, Hopkinton, MA, says the best move for many companies may be simply to wait. "The real convergence is going to be when your tools are consistent. NAS tools are totally different from SAN tools today," Taneja says. "We're still in the infancy stages on the NAS management side, and we're in the first generation of SAN management products."

This was first published in September 2003

Join the conversationComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.
    Back to top