iSCSI Host Connection Methods

The iSCSI initiators on the host system connect with targets on the array through the data ports on each controller. Each port is identified by its IP address. Normally, the NimbleOS selects the IP address for each connection automatically. Hosts connect to the Virtual Target IP addresses, then the connection is automatically redirected to an appropriate iSCSI Data IP address.

The default iSCSI host connection method for NimbleOS releases earlier than 2.0 is Manual, but the default iSCSI host connection method for NimbleOS 2.0 and later releases is Automatic. However, after upgrading from a pre-2.0 release, hosts will continue to connect manually to iSCSI data IP addresses. To remedy this, install the Nimble Host Integration Toolkit on supported hosts and then change the iSCSI host connection method from Manual to Automatic. The Nimble Connection Service (NCS) changes the iSCSI connections to connect to discovery IP addresses instead of data IP addresses, and NCS maintains the optimal number of connections. On the remaining hosts, change the iSCSI connections to connect to discovery IP addresses instead of data IP addresses. After all iSCSI connections are changed to connect to Virtual Target IP addresses, enable iSCSI connection rebalancing in order for NimbleOS to automatically rebalance iSCSI connections when distribution of connections becomes unbalanced.

If a Layer 2 inter-switch link that cannot handle the volume of iSCSI traffic is present, set up IP address zones before enabling the Automatic iSCSI host connection method. Generally speaking, a Layer 2 inter-switch link is used when traffic to different iSCSI data IP addresses goes through different switches on the same subnet.