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The key to building an effective iSCSI storage area network (SAN) platform is figuring out what you need in terms of capacity, multi-protocol support, scalability, advanced features and price. This piece takes a closer look at iSCSI SANs in the SMB market.

Midsized enterprises certainly have discovered iSCSI. Dickinson Wright, PLLC, a Michigan-based law firm, turned to iSCSI after the growing law firm grew frustrated with direct-attached storage (DAS). "Let's say it was simple but prone to disk failures," says Alan Hunt, manager of operations. The firm turned to an iSCSI storage area network (SAN) from EqualLogic (now Dell Inc.), with 70 TB of raw capacity. The iSCSI SAN proved simple to install and trouble-free to maintain, prompting the firm to install an iSCSI SAN in each of its seven locations and replicate between them for backup.

eDirect Impact Inc., Montgomery, TX, a service provider specializing in ediscovery, has assembled 100TB of iSCSI storage and is in the process of doubling it to 200 TB. "By next year, we could go to 300TB," says Sami Rahman, CEO. The company assembled its iSCSI SAN using a Reldata SAN head with an InforTrend disk array. The Reldata head also pulled in various JBOD capacity the company already had.

The iSCSI SAN proved simple to install and trouble-free to maintain, prompting the firm to install an iSCSI SAN in each of its seven locations.

"What we liked about iSCSI is the flexibility. It didn't require us to change our infrastructure. We didn't want to add more technology, like FC [Fibre Channel]. We just wanted to use what we had. And iSCSI gives us good performance," says Rahman.

AmeriVault Corp., Waltham, MA, a provider of remote backup, turned to iSCSI when it decided to give customers a lower cost option at a lower service level. "If we were going to offer a lower cost service, we needed to reduce our operating cost. The lower cost of iSCSI was attractive," says Kevin Harris, co-founder and CIO.

iSCSI goes mainstream

In 2007 Enterprise Strategy Group (ESG) declared iSCSI had gone mainstream based on its survey of over 500 organizations, in which 37% either had adopted or planned to adopt iSCSI SANs. Other analysts concur: "iSCSI has arrived. Its appeal is low cost and the ability to leverage the existing IP infrastructure," says Greg Schulz, senior analyst at the StorageIO Group, a research firmed based in Stillwater, MN.

Our twice yearly Storage Purchasing Intentions surveys report similar numbers for iSCSI adoption. In the most recent survey conducted last fall, 40% of respondents said they have implemented or planned to implement iSCSI storage in 2008.

"There is no doubt iSCSI is here to stay. It is easier to learn [than FC], quicker to install and easier to configure and manage," says Jeff Byrne, senior analyst, Taneja Group, Hopkinton, MA. And given iSCSI's lower cost, it is a natural for SMBs seeking networked storage.

The best iSCSI SANs also come loaded with goodies that cost extra in the FC world, like replication, snapshots, data deduplication and thin provisioning. "Some iSCSI SANs even have automated load balancing, which re-stripes and rebalances workloads," Byrne continues. Add built-in wizard-based graphical management tools and the best iSCSI SANs still cost significantly less than FC SANs.

Server virtualization boosts iSCSI

If low cost or ease of use doesn't drive companies to iSCSI, server virtualization might. Virtualization requires some form of networked storage if companies want the improved availability that server virtualization promises. Improved availability results from the ability to move virtual machines (VM) over the network to different physical servers should a physical server fail. If the data, however, is stored on disks directly attached to the failed physical server, then the organization is stuck. Through networked storage, such as an iSCSI SAN, the VM can continue to access its data on the SAN from wherever on the network it ends up.

Increasingly, vendors are taking advantage of virtualization by loading iSCSI SAN software on a VM running on a physical server with disk drives attached to it. "This is referred to as tin-wrapped software," says Schulz. Any organization adopting Windows Storage Server for iSCSI through Hewlett-Packard Co. or Dell is probably getting an iSCSI SAN as tin-wrapped software. "Many don't even know they are getting it because it is pre-packaged and integrated," he adds.

Through this approach, the business can get an almost instant iSCSI SAN consisting of the iSCSI VM and the disk drives attached to the physical host server. If the server has eight drives and each is a 1TB SATA drive, you now have an 8TB iSCSI SAN, which represents a significant chunk of storage for a small business and even many midsize enterprises. "You can do lots of variations on this," adds Schulz.

One variation: LeftHand Networks, recently acquired by HP, takes a physical cluster of three HP servers, which adds high availability, and loads its SANiQ iSCSI software on a VM running on the cluster.

The LeftHand approach does not necessarily produce a cheap solution; a single hardware/software node with a couple of terabytes of storage runs about $15,000. Most customers start with three nodes. Other iSCSI SANs, however, can be purchased for under $5000, even under $4000, including a terabyte or two of storage, making them suitable for almost any organization.

There are many ways to get an iSCSI SAN today. The big iSCSI vendors -- Dell/EqualLogic, NetApp Inc., EMC Corp., HP/LeftHand -- offer iSCSI products at a variety of prices. Smaller vendors like SANRAD Inc., Reldata Inc. and Nimbus offer iSCSI heads that connect to whatever disk arrays you put behind them. Some support a combination of storage protocols: iSCSI, FC, NAS and NFS. In addition, you will need an Ethernet switch, starting around $300, and an Ethernet NIC, less than $100, on each physical server. The iSCSI initiator, required for the server, already is included with most server operating systems. Analysts expect a native VMware Inc. iSCSI initiator in the next release of ESX.

"You certainly can put together a small iSCSI SAN for under $10,000 and probably for under $5,000 depending on how much storage capacity you want," says Byrne. iSCSI doesn't require deep technical skills either. The key is figuring out what you want in terms of capacity, multi-protocol support, scalability and various advanced features and how much you are willing to pay. The jump to 10Gbs iSCSI will cost significantly more. But at 1Gbs prices, cost should not be an obstacle in getting to iSCSI for midsize enterprises and even small businesses.

Alan Radding is a frequent contributor to

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