iSCSI SAN storage will remain popular with SMBs: An iSCSI tutorial

This tutorial looks at the factors driving adoption of iSCSI SANs today and what to consider before deploying iSCSI.

iSCSI storage area network (SAN) vendors and storage industry analysts alike have been praising iSCSI SANs as an ideal networked storage solution for small- to medium-sized business (SMBs) for years. Because it runs over IP, iSCSI does not require the specialized expertise of Fibre Channel; there is a variety of products on the market at SMB price points; the software initiators are built into all of the major operating systems; and the performance is more than adequate for many organizations.

In this iSCSI tutorial on iSCSI SAN storage, learn why many SMBs are turning to iSCSI SANs, what to look for in a product and whether or not an iSCSI SAN is a good choice for your organization.


iSCSI SAN storage in the mainstream
iSCSI SANs and server virtualization 
Virtual iSCSI SANs 
10 Gigabit Ethernet 


The benefits outlined above have made iSCSI SANs attractive to many SMBs. However, iSCSI storage is taking hold in larger companies as well. According to the 2010 Storage magazine Purchasing Intentions survey which focuses on larger companies, 40% of respondents already use iSCSI storage, and 41% plan to deploy iSCSI systems this year.

"You can't really point at any one thing that is driving deployment of iSCSI," said Greg Schulz, founder and senior analyst with the Storage IO Group. "It's the general maturity of the iSCSI ecosystem. The implementations have been refined, the products have been refined, the support, the interoperability, all of those things that deliver on the original value proposition have come to fruition. Because of that the acceptance of iSCSI has grown." Mark Peters, an analyst with Enterprise Strategy Group agreed. "A few years ago, I felt like I was always defending iSCSI," he said. "Now there is a satisfactory level of market acceptance."

Marc Staimer, president of Dragon Slayer Consulting, echoed this sentiment. "The argument about whether iSCSI is a good SAN interconnect isn't relevant -- it is," he said "There are millions of implementations now. It's proven. At the end of the day, it's a good, low-cost interconnect."

Editor's Tip: For more information about iSCSI SANs and SMBs, listen to our iSCSI SAN FAQ.


Vendors, analysts and users alike have cited the costs of networked storage as a barrier to server virtualization adoption. Hewlett-Packard (HP) Co.'s LeftHand Networks and Dell EqualLogic have positioned iSCSI SAN storage products as a lower cost alternative to Fibre Channel for smaller companies looking to deploy networked storage to support server virtualization. Overland Storage Inc. recently announced the release of the Snap Server SAN S2000 with VMware Inc. vSphere and Microsoft Corp. Hyper-V virtual server integration. Dell/EqualLogic's PS Series arrays feature Auto-Snapshot Manager/VMware Edition software integrated with VMware's Site Recovery Manager for automated replication and failover in VMware environments.

Though these products are presumably aimed at attracting users to iSCSI SAN storage in order to reap the benefits of server virtualization, Peters noted that users' decision-making is not so cut and dry. "I think other factors weigh more on people's decisions," he said. "For example, do they have experience with Fibre Channel? [This type of product] may be a factor if a company is starting from scratch, because of the lower cost. And virtualization is moving down into smaller and smaller businesses."

Also, many organizations may find that NFS is more suitable for their needs when moving toward server virtualization. "With block storage you have to set up LUNs, and in each LUN you have to set up RAID groups," said Staimer. "You have a lot of little details you need to set up. With NFS, you're just setting up your NAS shares -- it's really easy. From a user expertise point of view, NFS is more user friendly to a VM administrator than block storage is."

Peters advises users to keep their options open. "Why not a system that can do both NFS and iSCSI, it looks as if this is the direction everything is going in the next few years. What if you need an application in the next few years that only runs on one or the other?"

Editor's Tip: For more information about iSCSI SANs server virtualization, listen to sister site SearchDisasterRecovery's podcast on server virtualization strategies.


According to Staimer, products such as Pivot 3's Unified Virtual System and Seanodes' Virtual iSCSI SAN eliminate the time-consuming issues of cable management, switch management, and port management. "You are simplifying another aspect of the infrastructure," he said. "And because it's TCP/IP, iSCSI is a better fit in a closed loop, virtualized, end-to-end environment. It's much easier to intergrate." Staimer noted that for a SMB this benefit is not overstated. "The TCP/IP knowledge base is already there, so by definition it's easier for users," he said.

Editor's Tip: For more information about virtual iSCSI SANs, read sister site SearchStorage's article on Pivot3 and Seanodes' iSCSI storage products.


There is a perception that 10 Gigabit Ethernet may push users toward iSCSI SANs. However, experts agree that, today, the cost of 10 GigE is still too high to be a real driver. "10 Gigabit Ethernet is still extremely cost-prohibitive," said Schulz. "This flies in the face of the value prop of iSCSI. 95% of iSCSI implementations are software initiator based. So, when you decide to deploy 10 Gig you have to go out and by an adapter, and a 10 Gig switch, and the optics. So, you are pushing yourself close to the cost of Fibre Channel." Staimer agreed. "Until [10 Gigabit Ethernet] is the motherboard of the servers and cheap, you won't see it take off," he said.

Editor's Tip: For more information about iSCSI SAN storage, bookmark our special section on small and midsized SAN storage tips, news and research.

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