Users, vendors combine NAS, iSCSI

News from NetApp, Snap, FalconStor, String Bean Software

By Dave Simpson

Combining in the same device the benefits of file-based network-attached storage (NAS) and block-based storage area networks (SANs) via iSCSI is shaping up to be a trend in the end-user community.

Network Appliance kicked off the trend more than a year ago and now supports iSCSI on virtually all of its filers, including the F800, FAS200, FAS900, gFiler, and NearStore systems. Joel Reich, director of product marketing at NetApp, says that end-user interest in iSCSI support on NAS filers started to pick up around September of last year and that more than 2,200 users have downloaded iSCSI target software from NetApp's Website (for free). The company claims to have more than 300 production sites running iSCSI in conjunction with NAS, which NetApp refers to as "unified storage."

One of those sites is Cross Country Healthcare, a staffing services provider in Boca Raton, FL, that is running an iSCSI SAN in conjunction with NetApp NAS filers (an F820 and F940c clustered configuration).

According to Mike MacNeill, director of technical operations at Cross Country, the company runs applications such as SQL Server, Exchange, and some general file-serving applications on the iSCSI SAN, and runs other file-serving applications on traditional NAS.

Why iSCSI? "The main reason is that we needed a SAN, and the costs associated with Fibre Channel cards, cabling, and administration were too high," says MacNeill. (For details about Cross Country Healthcare's SAN/NAS implementation, see "Cross Country combines NAS, iSCSI," p. 12.)

In addition to Cross Country Healthcare, NetApp customers that are taking advantage of iSCSI support to create NAS/SAN (file/block) hybrids include Krispy Kreme, Navitaire, Trader Media Group, Textile Manufacturers, and Zoran Microelectronics. (Case studies are available at www.netapp.com.)

Network Appliance's Reich says that most of the sites using iSCSI are homogeneous Windows environments, with a little Linux and NetWare mixed in. "They use iSCSI to support applications that typically require [or perform better with] block access, such as SQL Server and Exchange, and they use NAS when performance is better with file-level I/O."

Reich also reports that most early adopters are using iSCSI software initiators without accelerator cards (although Network Appliance has tested iSCSI host cards from Adaptec, Alacritech, Intel, and QLogic).

Snap supports iSCSI

Since iSCSI is still primarily a low-end/workgroup solution, it's not surprising that Snap Appliance—the leader in NAS unit shipments—also recently announced support for iSCSI in version 3.0 of its Linux-based GuardianOS operating system, which runs on all of the company's Snap Servers. (GuardianOS 3.0 is included in the recently announced Snap Server 15000, but all of the company's NAS filers can be upgraded to the new software to enable combined file/block I/O.)

"NAS is a perfect vehicle to take advantage of iSCSI," says Jim Sherhart, a product manager at Snap. "Users can do only iSCSI, only NAS, or both, with GuardianOS 3.0."

Pricing for String Bean Software's WinTarget software is based on the number of iSCSI client servers receiving network-controlled disk from a single iSCSI target server. In the above example, the license would be $750.
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In addition to supporting block and file I/O, GuardianOS 3.0 includes two software features targeted at "unified" (iSCSI plus NAS) environments. Instant Capacity Expansion (ICE) provides on-demand scalability and provisioning without requiring a RAID rebuild, and Snap Server Manager (SSM) software can be used to discover, configure, and manage multiple Snap Servers across an enterprise from a single console.

The Snap Server 15000 can scale from 5TB to 29TB by linking up to seven Snap Disk 30SA expansion arrays. The company positions the 15000 for applications such as nearline storage and accelerated backup. (GuardianOS includes BakBone's NetVault backup software.) Pricing starts at $34,990.

iSCSI for WSS 2003

FalconStor Software recently began shipments of its iSCSI Storage Server software, which is designed for NAS filers based on Windows Storage Server 2003. "We've added an iSCSI block layer to existing NAS features," explains John Lallier, vice president of technology at FalconStor.

iSCSI Storage Server is a smaller, simpler derivative of FalconStor's flagship IPStor software that is designed for the small to medium-sized business (SMB) market. The iSCSI code includes IPStor features such as replication, synchronous mirroring, snapshots, a backup enabler, and storage provisioning. It also supports Microsoft's Volume Shadow Copy Service (VSS) via hardware providers or VSS agents.

One early beta site—Texas Tech University—is running iSCSI Storage Server software in a Dell PowerVault 775 NAS cluster to inexpensively consolidate storage onto an iSCSI SAN for the university's Web servers and departmental applications, according to Dustin Jordan, manager of server administration at Texas Tech.

So far, FalconStor has OEM agreements for iSCSI Storage Server with MaXXan Systems in the US, and Acer, Axiomtek, and Systex in Asia.

Windows servers = iSCSI targets

Start-up String Bean Software, in Montgomery Village, MD, is taking a unique approach to iSCSI SANs for SMBs with its WinTarget software, which enables any Windows server with local disk to be treated as an iSCSI target—including NAS filers based on Windows Storage Server 2003. Because the software is integrated with Windows, users can leverage the Windows Disk Management tools in an iSCSI SAN environment. The software was released (and the company was officially launched) last month.

"WinTarget software allows a Windows server to share its local disk resources over an Ethernet network via iSCSI," explains Thieu Le, president and CTO of String Bean, "and you don't need specialized hardware [although WinTarget can be used in conjunction with some iSCSI accelerator cards]." Features include support for dynamic LUNs, IPSec encryption for security, and iSNS for iSCSI SAN management.

WinTarget is priced at $250 per server client; an unlimited client license is available for $2,500.

The company claims to have more than 250 beta sites, but one of its early licensees may provide the start-up with even greater visibility: Microsoft has licensed WinTarget for internal use.

For more information about iSCSI, see the following articles that have appeared in:

"Who's using IP storage, and why?" May 2004, p. 18
"Alacritech accelerates iSCSI," April 2004, p. 8
"iSCSI attracts early adopters," March 2004, p. 20
"Network security implications of IP SANs," March 2004, p. 42
"Influx of iSCSI products continues," February 2004, p. 8
"ADIC offers iSCSI backup options," February 2004, p. 8
"iSCSI planning: Targets, availability, and security," February 2004, p. 34
"iSCSI and TCP/IP offload engines," January 2004, p. 40
"iSCSI accelerates the transition to network storage," January 2004, p. 30

Cross Country combines NAS, iSCSI

Cross Country Healthcare, a staffing services provider in Boca Raton, FL, is buying into Network Appliance's concept of "unified storage," which means combining traditional file-based network-attached storage (NAS) functionality with block-based iSCSI in the same filer. The company has a NetApp F820 and an F940c clustered NAS configuration attached to seven servers (Windows and Linux) with about 400GB of capacity.

Applications such as SQL Server, Exchange, and some general file-serving applications run on an iSCSI storage area network (SAN), while other file-serving applications run on traditional NAS.

Mike MacNeill, director of technical operations at Cross Country, says that the main reason that he went with iSCSI was that it needed a SAN to consolidate storage, and Fibre Channel host cards, cabling, and administration were too complex and costly. "Fibre Channel HBAs [host bus adapters] cost three times iSCSI HBAs," he says. Although he tested a Fibre Channel SAN configuration, the company decided to replace it with the iSCSI SAN.

Cross Country uses iSCSI HBAs (accelerator cards) from Adaptec. "We tried Microsoft's iSCSI software initiators and Linux iSCSI initiators, but at high loads we noticed a 10% to 15% CPU utilization—not enough to cripple the machine, but it was significant so we decided to go with the Adaptec cards [which cost less than $500]." With the Adaptec cards, host CPU utilization never goes above 3%, according to MacNeill.

With the iSCSI setup, "we're getting much better performance than we had been getting with local [direct-attached] disk, although it isn't quite as fast as Fibre Channel," says MacNeill. To optimize iSCSI performance, Cross Country separates the iSCSI Ethernet SAN from its primary Ethernet LAN. An additional benefit of the iSCSI SAN was a 90% reduction in wasted disk space versus the company's previous direct-attached storage configurations. "I'm a huge fan of iSCSI," MacNeill concludes.

This article was originally published on June 01, 2004