iSCSI storage arrays provide flexible virtualisation.

Author:Sherbak, Tim
Position:Storage Expo 2008

According to Gartner, virtualisation will have the greatest impact on IT infrastructures and operations over the next five years(1). In particular, an increasing number of enterprises are building flexible storage infrastructures using Internet SCSI (iSCSI) and advanced virtualisation technologies. The advent of iSCSI, a flexible and powerful storage area network (SAN) protocol has enabled breakthrough virtual storage designs that parallel the advanced designs of server virtualisation technologies. There are three simple reasons why more and more enterprises of all sizes are choosing to implement iSCSI storage arrays: Scalability, simplified storage management and cost.

iSCSI protocol enables the implementation of advanced storage virtualisation technologies where storage is virtualised at the storage device level. This approach helps achieve scalable performance and capacity, while reducing overall management by aggregating multiple controllers into a cooperating set of resources by virtualising volumes not only across disks within a controller but also across storage systems in a SAN. Such "scale-out" designs are virtually nonexistent in the Fibre-Channel SAN world due to the inherent architectural constraints in Fibre-Channel network deployments.

An iSCSI storage architecture is particularly appealing in a virtualised server environment because the scale-out architectures of both server and storage infrastructures complement each other, providing an end-to-end virtualised infrastructure. A virtualised server and storage environment is particularly adaptable to changing business requirements by providing non-disruptive workload migration and balancing across all physical server and storage resources. Complementary server and storage virtualisation built on iSCSI SANs creates a fully abstracted pool of physical resources--one that provides higher performance, scalability and flexibility compared to classic storage array infrastructures.

Another benefit of an iSCSI system is that it simplifies storage management. In an iSCSI SAN, a storage group of multiple arrays appears to...

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