Example iSCSI configurations
Configure your Storwize® V3700 in a network that uses Internet Small Computer System Interface (iSCSI).



In this example, host 1 does not use multipathing. A volume in the Storwize V3700 system appears as four separate devices in host 1. The host selects one device, which corresponds to a particular IP address at a Storwize V3700 node port, 10.10.1.10. If a connection between the host and this Storwize V3700 port is broken (the link at X is broken), an error is recorded on host 1 for that volume. No Storwize V3700 state changes or IP failover occurs.
Host 2 uses multipathing. A volume in the Storwize V3700 system appears as a single device to the applications on host 2, even though the multipathing driver can detect four separate devices for each volume. The multipathing driver selects one or more of these devices. If the connection between the host and one Storwize V3700 node port is lost, the multipathing driver can select an alternative path to the Storwize V3700. The connection between the host and Storwize V3700 continues without error. However, host 2 has only one host interface adapter. Therefore, host 2 reports errors (such as the link at Y is broken) if the connection between that host interface adapter and the network is lost.
Host 3 uses multipathing and redundant host interface adapters. If a host interface adapter fails, the multipathing driver can still find paths from the host to a volume in the Storwize V3700 system and the application can continue without error. Because the host interface adapters are connected to different IP networks, the overall configuration can tolerate a single network failing without errors occurring on host 3.
Multipathing drivers are not required to do system maintenance when Storwize V3700 nodes are removed or replaced. However, multipathing host drivers are required for load balancing and for surviving host interface adapter, link, or network failures.