vSphere Storage - ESXi 5.1 - Documentation - VMware

vSphere Storage
After you configure the dependent hardware iSCSI adapter, the discovery and authentication data are passed
through the network connection, while the iSCSI traffic goes through the iSCSI engine, bypassing the network.
The entire setup and configuration process for the dependent hardware iSCSI adapters involves these steps:
1 View the dependent hardware adapters.
n To view in the vSphere Client, see “View Dependent Hardware iSCSI Adapters,” on page 83.
n To view in the vSphere Web Client, see “View Dependent Hardware iSCSI Adapters in the vSphere
Web Client,” on page 83.
If your dependent hardware adapters do not appear on the list of storage adapters, check whether they
need to be licensed. See your vendor documentation.
2 Determine the association between the dependent hardware adapters and physical NICs.
n For the vSphere Client, see “Determine Association Between iSCSI and Network Adapters,” on
page 84.
n For the vSphere Web Client, see “Determine Association Between iSCSI and Network Adapters in
the vSphere Web Client,” on page 84.
Make sure to note the names of the corresponding physical NICs. For example, the vmhba33 adapter
corresponds to vmnic1 and vmhba34 corresponds to vmnic2.
3 Configure networking for iSCSI.
See “Setting Up iSCSI Network,” on page 87.
Configuring the network involves creating a VMkernel interface for each physical network adapter and
associating the interface with an appropriate iSCSI adapter.
4 (Optional) Enable Jumbo Frames.
See “Using Jumbo Frames with iSCSI,” on page 97.
5 Configure discovery information.
See “Configuring Discovery Addresses for iSCSI Adapters,” on page 99.
6 (Optional) Configure CHAP parameters.
See “Configuring CHAP Parameters for iSCSI Adapters,” on page 102.
Dependent Hardware iSCSI Considerations
When you use dependent hardware iSCSI adapters with ESXi, certain considerations apply.
n 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.
n If you use a third-party virtual switch, for example Cisco Nexus 1000V DVS, disable automatic pinning.
Use manual pinning instead, making sure to connect a VMkernel adapter (vmk) to an appropriate physical
NIC (vmnic). For information, refer to your virtual switch vendor documentation.
n 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 heavy load, enable flow
control to avoid performance degradation.
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.
To enable flow control for the host, use the esxcli system module parameters command. For details, see
the VMware knowledge base article at http://kb.vmware.com/kb/1013413
82 VMware, Inc.