1.3 iSCSI SAN Configurations

iSCSI provides a great deal of flexibility and a number of different configuration options.

Three common iSCSI configurations are illustrated below, along with the advantages and disadvantages of each.

Figure 1-3 Non-Dedicated Ethernet Configuration

The nondedicated Ethernet configuration illustrated above is the least expensive iSCSI configuration option because you can leverage existing Ethernet hardware to create a low-cost SAN. Nondedicated Ethernet does not provide the same level of performance as dedicated Ethernet or iSCSI router configurations because disk requests and LAN traffic use the same network hardware.

Figure 1-4 Dedicated Ethernet Configuration

The dedicated Ethernet configuration illustrated above is more expensive than non-dedicated Ethernet, but provides better performance because separate Ethernet hardware is required for the SAN. Disk requests and LAN traffic each have their own dedicated Ethernet hardware.

Figure 1-5 iSCSI Storage Router Configuration

The iSCSI storage router configuration illustrated above is the most expensive iSCSI configuration option, but it provides the best performance. The iSCSI router configuration utilizes standard Ethernet hardware. Servers are connected via Ethernet connections to the iSCSI router, which is part of the shared storage system.