iSCSI - beyond the hype

by Alistair Crooks

Abstract

The practice of accessing storage across a network is not new - we have been using network file systems for a number of decades, and, more recently, block storage has been used across networks, commonly known as Storage Area Networks (SANs). Data centres have primarily been the principal users of SANs, due to the high cost of components and administration, dedicated communication costs and infrastructure. The arrival several years ago of iSCSI, which uses TCP/IP as the transport mechanism to route the SCSI protocol, has changed all of that - SANs are now a low-cost option, and add significant options to backup, business continuity, and disaster recovery which were previously only available at the high end of the market. This paper describes iSCSI in general - the target and initiator components, its architecture and usage models, areas of concern, and possible future areas of opportunity, and then goes on to describe the various open source offerings which are available. It finishes by describing the NetBSD iSCSI target, a portable userland implementation of an iSCSI target, and its interactions with initiators running on other operating systems.

Author bio

Alistair has been involved with NetBSD for 13 years, and a NetBSD developer for 9 years, when he started the NetBSD Packages Collection. He is the lead member of the NetBSD Core team and has been President of the NetBSD Foundation for the last 18 months. He wrote the user management suite of programs used by NetBSD and OpenBSD, various editors, and the NetBSD iSCSI target. He lives in Berkshire in the UK with his two guinea pigs, two children and a wife, and enjoys the finer things in life - Rangers, pub quizes and curries.

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