Several common misperceptions have persisted regarding how iSCSI compares to traditional Fibre Channel deployments. With iSCSI becoming an increasingly mainstream technology and large vendors like Dell and EMC offering iSCSI products, these notions are no longer necessarily true.
Performance: The first misperception is that iSCSI cannot provide the performance necessary for enterprise applications. Many key applications have random I/O data patterns, and the performance bottleneck ends up being the time it takes to write and read data from hard disk drives, not the network bandwidth.
Manageability: Another misperception is that iSCSI is more difficult to manage than Fibre Channel. The management applications for iSCSI SANs have become intelligent, wizard based or even self managing removing much of the complexity of day to day activities. Additionally, because iSCSI utilizes standard Ethernet equipment and because many IT staffs are more familiar with Ethernet than Fibre Channel, iSCSI networks are often easier to manage.
Network security: A very common misperception is that iSCSI SANs are not as secure as Fibre Channel SANs. In fact, when logically or physically separated, iSCSI networks are just as secure as Fibre Channel.
Read More about how iSCSI is Changing the Economics of Storage