No storage devices are visible with Broadcom iSCSI offload-enabled adapters (1025644)
When using Broadcom network interfaces with Hardware iSCSI Offload capabilities such as BCM5709 and BCM57711, each of the network interfaces shows up as individual storage adapters in the Configuration tab of an ESX host and each adapter also has an individual IQN. However, when you configure the adapter for iSCSI, you observe these symptoms:
- You are unable to add any discovery addresses.
- When observing the Dynamic or Static Discovery tabs in the iSCSI Initiator Properties window, you see the message:
The host bus adapter is not associated with a vmknic. To configure targets the adapter should be associated with a vmknic. Refer to the VMware documentation to associate the adapter with a vmknic.
- None of the adapters show associated storage devices.
- Dependent Hardware iSCSI Initiators which are regular network cards where certain iSCSI operations can be offloaded from the CPU on the host to the network card.
- Software iSCSI initiators as these cards can be used as regular network cards.
Dependent Hardware iSCSI Initiators
- With ESX/ESXi 4.x and 5.0 these network cards configured as dependent Hardware iSCSI initiators do not support Jumbo Frames (MTU 9000) or IPv6 while they are supported when the network cards configured as software iSCSI initiators.
- When you use any dependent hardware iSCSI adapter, performance reporting for a NIC associated with the adapter might show little or no activity, even when iSCSI traffic is heavy. This behavior occurs because the iSCSI traffic bypasses the regular networking stack.
- The Broadcom iSCSI adapter performs data reassembly in hardware, which has a limited buffer space. When you use the Broadcom iSCSI adapter in a congested network or under load, enable flow control to avoid performance degradation.
Note: Flow control manages the rate of data transmission between two nodes to prevent a fast sender from overrunning a slow receiver. For best results, enable flow control at the end points of the I/O path, at the hosts and iSCSI storage systems.
Software iSCSI Initiators
- Use two or more dedicated network cards for iSCSI.
- These network cards should be configured on the same network segment as the storage processors on your iSCSI array to avoid routing.
- If possible connect the iSCSI network cards to different physical switches for additional redundancy.
- VMware recommends using port binding (also known as a 1:1 mapping) to ensure iSCSI paths can be correctly multipathed by the host. This configuration is covered in the iSCSI SAN Configuration guides.
- If you are using different networks for your iSCSI vmkernel ports then they have to be on separate vSwitches. For more information, see Configuring a VMkernel port and enable vMotion via command line (1006989).
For more information on configuring your system to use iSCSI, see the iSCSI SAN Configuration Guide.