White Papers

BP1028 EqualLogic iSCSI for Fibre Channel Professionals 2
1 Overview
As data storage has become central to any successful computer based solution, advanced
technologies for connecting computing resources to data have matured over the last four decades.
From early storage connection protocols that utilized parallel data transmission such as SCSI and ATA
that connected storage devices directly to individual computing resources through today’s modern
distributed storage networking solutions, everything has revolved around one key goal: provide
access to data in ever faster, more secure, and less expensive ways.
Storage networks provide several unique benefits over direct attached storage including:
• Increased throughput
• Improved flexibility
• Greater scalability
• Centralized management
• Multi-host clustering
While storage networking – the use of a shared storage and communications infrastructure – has
been around for some time, it became increasingly popular with the advent of the Fibre Channel (FC)
standard in the early to mid-1990s. Since then FC has been the predominant shared storage network
protocol in use… that is, until the IP SCSI (iSCSI) storage networking protocol was developed in the
early 2000’s.
The FC and iSCSI protocols both use an updated version of the original SCSI protocol adopted in the
mid 1980’s for directly attaching storage devices to individual computing resources. Even so, both
Storage Area Networking (SAN) standards use different methods of transmitting these SCSI commands
between the computing resources and the storage resources. This paper provides an overview of the
iSCSI protocol and concepts, as they pertain to the Dell EqualLogic PS Series of virtual storage arrays,
for storage administrators with FC storage experience.
Fibre Channel over Ethernet (FCoE) is another storage protocol for carrying SCSI commands, and has
features similar to both FC and iSCSI. However, FCoE requires additional features such as Data Center
Bridging (DCB) and 10 Gb Ethernet to properly support it and detailed discussion of these concepts are
outside of the scope of this paper. This paper will focus on the similarities and differences between
FC and EqualLogic iSCSI SAN concepts.
While some of the concepts are similar for both FC and iSCSI protocols, there are differences in
terminology and capability that must be understood to successfully design and manage an iSCSI
solution such as the Dell EqualLogic PS Series SAN. The goal of this paper is not necessarily to
convince anyone that is well entrenched in a FC storage environment into migrating to iSCSI, but
simply to help those that are considering the move, or have already made that decision, and to enable
a smooth adoption of EqualLogic iSCSI.
2 Audience
This paper is intended for the experienced storage networking administrator or SAN architect who is
planning to purchase or already has purchased a Dell EqualLogic iSCSI storage solution. This paper
assumes that the reader has prior experience in, and a thorough understanding of traditional FC
storage area network architecture and its related concepts. For further definition of EqualLogic-
specific terms, see Appendix A.