Figure 6. Single iSCSI attached server
To attach or host an xSeries® or IBM® BladeCenter™ server via iSCSI to an iSeries™, hardware must be installed in both the iSeries and the hosted system. The hardware required at each end is an iSCSI host bus adapter (HBA) or iSCSI adapter. These two adapters are connected via an Ethernet switch, using standard Ethernet cables. The simplest form of the physical connection between a hosted system and an iSeries server is illustrated in Figure 6.
Figure 6. Single iSCSI attached server
The xSeries or IBM BladeCenter server known as the hosted system has an initiator iSCSI HBA installed. This adapter has an Ethernet network interface and it is connected via an Ethernet switch to the target iSCSI HBA installed in the iSeries server. The hosted system is a diskless server. The virtual disks and virtual removable media devices are hosted or provided by the iSCSI HBA for iSeries. The SCSI commands to access these devices are packaged in TCP/IP frames and travel from the hosted system to the iSCSI HBA for iSeries over the Ethernet network. This mode of communication is known as Internet SCSI or iSCSI.
The iSCSI attached servers are configured in i5/OS™ objects. For more information about these objects, see Software concepts.
i5/OS can locate and manage remote systems by sending commands to the service processor of the remote system over an Ethernet network. IBM Director is used for these functions and must be installed and running on all partitions that are connected to iSCSI attached host bus adapters (HBAs). For more information, see Remote server discovery and management.
Two distinct networks are illustrated in Figure 6. The iSCSI network uses an isolated switch. The service processor connection uses an external network (shared network). There does not have to be two distinct networks. For example, the service processor connection could use the same isolated switch as the iSCSI network. This is one way to secure the service processor connection. However, the i5/OS LAN adapter would not be available for other applications on the external network.
Both types of networks should be secured. For more information about security for iSCSI attached servers, see Security concepts.