iSCSI breaks through all market tiers

iSCSI-based IP SANs are also crossing operating system boundaries and going beyond small Windows environments.

By Farid Neema

Introduced only a few years ago, iSCSI SANs have clearly hit the mainstream and are now hosting virtually all types of applications, although e-mail, Web applications, and Microsoft Exchange are still the most popular.

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A recent survey conducted by Peripheral Concepts also reveals that iSCSI SAN implementations extend beyond Windows and NT to all open operating systems, including Unix and Linux. (For more information on how the survey was conducted., see “iSCSI survey methodology,” p. 31.)

Of the total survey population, 37% have implemented an iSCSI SAN, compared to less than 17% one year ago. However, equally surprising, 28% are not sure what an iSCSI SAN is, and 18% know what it is yet are unaware of their company’s iSCSI plans. Another 15% of the respondents have no plans to implement iSCSI (see figure, below). Market penetration involves all business tiers, challenging the early belief that iSCSI would only attract small and medium-sized sites. Segmenting by site disk capacity shows that iSCSI SANs have a wider presence in higher-capacity tiers, with a peak in Tier 3 (51TB-200TB). Tier-3 sites had more than a 60% penetration (including those sites that plan to implement iSCSI), with less than 20% having no plans to implement iSCSI (see figure, upper right). Also, although iSCSI’s popularity started in Windows environments, it has been extended to Unix and Linux. For example, iSCSI has been implemented by about 40% of sites with a majority of their storage connected to Unix platforms (see figure on p. 30).

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When asked to rate the potential of iSCSI SANs to solve one or more of their major storage problems, more than half of the larger sites rate it “very” or “extremely” important, versus less than one-third in capacity Tiers 1 and 2 (see figure on p. 30).

Selection criteria

Factors driving the growth in iSCSI adoption include the continuing need to reduce storage complexity while being able to utilize unused disk capacity. In addition, iSCSI leverages existing Ethernet cabling and network components, using both existing infrastructure and staff and eliminating the need to install another (e.g., Fibre Channel) network.

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Concerns about availability/reliability and security, which initially hindered the adoption of iSCSI SANs, no longer constitute obstacles. In fact, availability/reliability and security (as well as the ability to use existing networks) are among the top benefits and features cited by users in the Peripheral Concepts survey (see figure on p. 30).

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Other benefits and features cited by survey respondents include

  • Ease of management: Networked storage reduces the number of physical devices to manage and simplifies storage management, data sharing; and storage provisioning; and
  • Higher availability: Most iSCSI networks provide near-continuous data availability, offering redundant data paths between servers and storage, and support server clusters and RAID arrays with fail-over capability.

    Most of the earlier performance problems associated with iSCSI-based IP SANs have been solved by increased network speed: 100Mbps IP networks gave way to 1Gbps Ethernet in 2005 and 2006, and 10Gbps networks will prevail in 2007 and 2008 (see figure, left). And in rare instances, users install iSCSI-TCP/IP acceleration cards to boost performance.

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    And, according to the survey, there is hardly any application that is excluded from iSCSI SANs (see figure, above).


    Consolidation makes logical disks appear as locally attached hard drives for improved storage utilization and administrative efficiency through storage, file, and/or server virtualization. Consolidation facilitates rapid deployment of new storage resources and enables SAN-based backup functionality and advanced storage management capabilities.

    Consolidating storage in a single pool is not a new trend, but what is relatively recent is the consolidation of SAN and NAS, sometimes referred to as “unified storage.” The goal of SAN-NAS consolidation is to effectively use all available capacity across heterogeneous storage devices, allow access to this storage via block or file protocols, simplify allocation and management, and reduce the costs of managing storage over time.

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    In the Peripheral Concepts survey, 36% of the population has consolidated at least part of their SAN and NAS environments today (compared to only20% in last year’s survey), and another 31% plan to consolidate within the next year (see figure, below). The survey reveals that performance, cost, and scalability are the top factors or reasons for users choosing to consolidate.

    IP Storage has clearly entered the IT mainstream. Solutions are available from a wide variety of vendors, including all of the leading storage vendors as well as many start-ups. The emergence of low-cost iSCSI SANs means that IT professionals now have SAN options for a broader range of environments. Storage consolidation, simplified data protection, and improved data management are some of the key drivers behind iSCSI adoption. With the extended deployment of 1Gbps and 10Gbps IP networks, performance is no longer an issue. As the technology matures, iSCSI-based networks will continue to displace direct-attached storage (DAS) in high-end data centers and mission-critical Unix and Linux environments.

    Farid Neema is president of Peripheral Concepts Inc. (www.periconcepts.com). This article was excerpted from the firm’s “iSCSI and SAN” report.

    iSCSI survey methodology

    The primary objective of the Peripheral Concepts survey was to determine the adoption rate of iSCSI SANs and to understand why users chose it as opposed to alternatives such as Fibre Channel SANs, and in what application environments. The survey and report also analyze IT managers’ selection criteria and requirements, as well as networked storage consolidation trends.

    The survey targeted IT managers having storage management or data-protection responsibilities for IT operations with a minimum of 1TB of raw disk storage. More than 4,000 qualified managers answered the full screening survey of a dozen questions. We selected more than 200 individuals representing sites mostly in the 1TB to 200TB disk capacity range, with an attempt to include a sufficient number of representatives from each of 10 targeted industries. The full survey consisted of more than 60 questions, and we received 117 qualified responses.

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    The survey population was questioned on their storage configurations and implementation plans. For the selected population of 117 sites, the survey provides statistics on budgets, ranks issues, and requirements, and analyzes storage trends.

    Site profiles

    The “selected population” survey respondents for the most part were within the 1TB to 1 petabyte range (see figure). Sites with capacities between 1TB and 200TB are what Peripheral Concepts refers to as small to medium-sized businesses (SMBs). About 88% of the selected sites are in the 1TB to 200TB range. The survey analyzed responses by disk capacity range, both corporate and site capacity, and by industry.

    The total annual IT budget was less than $100,000 for 6% of the selected population and more than $20 million for 16% of the population, with a median in the range of $2 million to $3 million.

    This article was originally published on March 01, 2007