Storage Basics: iSCSI Page 2
InfiniBand is a nascent connectivity solution, and not many organizations are ready to become early adopters in its storage and connectivity solutions at this point. Though InfiniBand may emerge as the ideal connectivity solution for diskless clusters in the future, it will likely not impact either the Fibre Channel or iSCSI markets for many years.
Other technologies such as Fibre Channel over IP (FCIP), and Internet Fibre Channel Protocol (iFCP) stand to offer the same distance capabilities as iSCSI, without the potential throughput and latency concerns that are associated with iSCSI. However, it should be noted that iSCSI is a client/server connection oriented protocol, whereas FCIP is a gateway-to-gateway protocol. FCIP is an encapsulation protocol used for transporting Fibre Channel frames over TCP/IP networks. FCIP's main purpose is to connect Fibre Channel SANS to IP networks thereby extending the distance capabilities of pure fibre channel SANs.
While iSCSI, FCIP, and iFCP all appear to be similar technologies, their ideal implementation scenarios are very different. None of these connectivity protocols offer any inherent security, and will all require a security protocol such as IPSec to protect the data they are transmitting.
Naturally the use of iSCSI provokes some questions and concerns. For example, if you need to retrieve the data from a data warehouse farm in California, and you are in New York, what are the performance ramifications and what will the latency be upon executing an application?
Another major consideration is that of security. Is running iSCSI over a VPN the only safe way to transport storage data? What sort of latency and performance issues will using iSCSI over an IPSec based VPN create? On a more subtle level, but still of concern, is whether third-party data farms will accommodate iSCSI, and who will be the third-party iSCSI players providing this service?
Notwithstanding these concerns, all of which are addressable in some form or another, iSCSI holds a lot of promise, but there will be performance challenges in executing large-scale implementations. That said, the implementation costs of iSCSI are low enough that it will likely appeal to IT shops that may not have the budget for Fibre Channel.