vsphere-esxi-vcenter-server-55-storage-guide

Chapter 13 Booting from iSCSI SANIsolated iSCSI and Management NetworksWhen you configure isolated iSCSI and management networks, follow these guidelines to avoid bandwidthproblems.• Your isolated networks must be on different subnets.• If you use VLANs to isolate the networks, they must have different subnets to ensure that routing tablesare properly set up.• VMware recommends that you configure the iSCSI adapter and target to be on the same subnet. If youset up the iSCSI adapter and target on different subnets, the following restrictions apply:• The default VMkernel gateway must be able to route both the management and iSCSI traffic.• After you boot your host, you can use the iBFT-enabled network adapter only for iBFT. You cannotuse the adapter for other iSCSI traffic.• Use the first physical network adapter for the management network.• Use the second physical network adapter for the iSCSI network. Make sure to configure the iBFT.• After the host boots, you can add secondary network adapters to both the management and iSCSInetworks.Change iBFT iSCSI Boot SettingsIf settings, such as the IQN name, IP address, and so on, change on the iSCSI storage or your host, updatethe iBFT. This task assumes that the boot LUN and the data stored on the LUN remain intact.Procedure1 Shut down the ESXi host.2 Change iSCSI storage settings.3 Update the iBFT on the host with the new settings.4 Restart the host.The host boots using the new information stored in the iBFT.Troubleshooting iBFT iSCSI BootThe topics in this section help you to identify and solve problems you might encounter when using iBFTiSCSI boot.Loss of System's Gateway Causes Loss of Network ConnectivityYou lose network connectivity when you delete a port group associated with the iBFT network adapter.ProblemA loss of network connectivity occurs after you delete a port group.CauseWhen you specify a gateway in the iBFT-enabled network adapter during ESXi installation, this gatewaybecomes the system's default gateway. If you delete the port group associated with the network adapter, thesystem's default gateway is lost. This action causes the loss of network connectivity.SolutionDo not set an iBFT gateway unless it is required. If the gateway is required, after installation, manually setthe system's default gateway to the one that the management network uses.VMware, Inc. 113