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Storage August 2006 Special Supplement
The TCP/IP protocol
iSCSI uses TCP/IP instead of a proprietary storage protocol such as FC. As a result, iSCSI SANs can be built with commodity network components, eliminating the need for costly FC host bus adapters (HBAs), which are typically priced between $800 and $1,200, and FC switches. In fact, most servers are equipped with dual on-board gigabit network adapters and gigabit switches are available for less than $500. A regular network admin can easily manage the iSCSI storage network rather than requiring the help of an FC expert.
iSCSI products, especially from pure iSCSI players like EqualLogic Inc., Intransa Inc., LeftHand Networks and StoneFly, focus on simplified storage administration, providing wizard-based configuration and plain English dialogues for tasks like storage provisioning and expansion. Despite the attention to simplicity and low cost, almost all first-generation iSCSI arrays provide sophisticated data protection capabilities, including mirroring, snapshots and remote replication.
The vast majority of iSCSI deployments today are on Windows, followed by Linux, reports Dale. "Unix vendors were initially slow to embrace iSCSI, but that's changing fast," he says. One of the reasons iSCSI is predominantly seen in Windows environments is Microsoft Corp.'s firm support of iSCSI since its ratification as a standard in 2003. With the 2.0 release of its iSCSI
While SMBs use iSCSI SANs as their primary storage, large enterprises use iSCSI to complement their FC storage for less mission-critical departmental apps, remote offices and data protection purposes. Typical applications for iSCSI are messaging apps like Microsoft Exchange, databases, Web apps, file serving and disk-to-disk backup.
This was first published in August 2006