IT organizations have three main choices when it comes to disk storage, including direct attached storage (DAS), networked attached storage (NAS) and Fibre Channel-based storage area networks (SAN). iSCSI adds to the mix by offering another choice for block-based SAN.
Despite the simplicity and lower costs of iSCSI, Fibre Channel (FC) SAN is not going to vaporize anytime soon. Users have major investments in infrastructure (Wikibon estimates are $25B in installed assets) and skill sets built around FC. As such there is no compelling business case for converting in the near to mid-term. Indeed FC will continue to evolve as both FC and FCoE and be the primary choice to deliver performance and reliability levels required by many applications.
DAS, however remains a multi-billion dollar marketplace today and will be affected by iSCSI. The 1:1 relationship between servers and storage within collocated and rack mounted server environments is ripe for change. iSCSI will allow small and medium-sized operations to improve boot management, simplify backup, automate recovery and enable a variety of 'light' SAN services. This is good news for several reasons, not the least which is it will allow smaller organizations to develop SAN-oriented best practices while larger organizations can support the evolution of iSCSI-based services. This will pressure FC-based infrastructure suppliers to continue to drive cost out of solutions.
Action Item: Users should aim iSCSI at DAS to improve the automation of distributed storage infrastructure that doesn't scale and can't be shared. As well, organizations with enough critical mass should consider iSCSI for blade server environments where often the cost of SAN is prohibitive.
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