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

Chapter 11 Configuring iSCSI Adapters and Storage• When using separate vSphere switches to connect physical network adapters and VMkernel adapters,make sure that the vSphere switches connect to different IP subnets.• If VMkernel adapters are on the same subnet, they must connect to a single vSwitch.• If you migrate VMkernel adapters to a different vSphere switch, move associated physical adapters.• Do not make configuration changes to iSCSI-bound VMkernel adapters or physical network adapters.• Do not make changes that might break association of VMkernel adapters and physical networkadapters. You can break the association if you remove one of the adapters or the vSphere switch thatconnects them, or change the 1:1 network policy for their connection.iSCSI Network TroubleshootingA warning sign indicates non-compliant port group policy for an iSCSI-bound VMkernel adapter.ProblemThe VMkernel adapter's port group policy is considered non-compliant in the following cases:• The VMkernel adapter is not connected to an active physical network adapter.• The VMkernel adapter is connected to more than one physical network adapter.• The VMkernel adapter is connected to one or more standby physical adapters.• The active physical adapter is changed.SolutionFollow the steps in “Change Network Policy for iSCSI in the vSphere Web Client,” on page 87 to set up thecorrect network policy for the iSCSI-bound VMkernel adapter.Using Jumbo Frames with iSCSIESXi supports the use of Jumbo Frames with iSCSI.Jumbo Frames are Ethernet frames with the size that exceeds 1500 Bytes. The maximum transmission unit(MTU) parameter is typically used to measure the size of Jumbo Frames. ESXi allows Jumbo Frames withthe MTU up to 9000 Bytes.When you use Jumbo Frames for iSCSI traffic, the following considerations apply:• The network must support Jumbo Frames end-to-end for Jumbo Frames to be effective.• Check with your vendors to ensure your physical NICs and iSCSI HBAs support Jumbo Frames.• To set up and verify physical network switches for Jumbo Frames, consult your vendor documentation.The following table explains the level of support that ESXi provides to Jumbo Frames.Table 11‐3. Support of Jumbo FramesType of iSCSI AdaptersSoftware iSCSIDependent Hardware iSCSIIndependent Hardware iSCSIJumbo Frames SupportSupportedSupported. Check with vendor.Supported. Check with vendor.VMware, Inc. 89