iBFT iSCSI Boot Overview

ESXi hosts can boot from an iSCSI SAN using the software or dependent hardware iSCSI adapters and network adapters.

To deploy ESXi and boot from the iSCSI SAN, the host must have an iSCSI boot capable network adapter  that supports the iSCSI Boot Firmware Table (iBFT) format. The iBFT is a method of communicating parameters about the iSCSI boot device to an operating system.

Before installing ESXi and booting from the iSCSI SAN, configure the networking and iSCSI boot parameters on the network adapter and enable the adapter for the iSCSI boot. Because configuring the network adapter is vendor specific, review your vendor documentation for instructions.

When you first boot from iSCSI, the iSCSI boot firmware on your system connects to an iSCSI target. If login is successful, the firmware saves the networking and iSCSI boot parameters in the iBFT and stores the table in the system's memory. The system uses this table to configure its own iSCSI connection and networking and to start up.

The following list describes the iBFT iSCSI boot sequence:
1 When restarted, the system BIOS detects the iSCSI boot firmware on the network adapter.
2 The iSCSI boot firmware uses the preconfigured boot parameters to connect with the specified iSCSI target.
3 If the connection to the iSCSI target is successful, the iSCSI boot firmware writes the networking and iSCSI boot parameters in to the iBFT and stores the table in the system memory.
NOTE The system uses this table to configure its own iSCSI connection and networking and to start up.
4 The BIOS boots the boot device.
 5 The VMkernel starts loading and takes over the boot operation.
6 Using the boot parameters from the iBFT, the VMkernel connects to the iSCSI target.
7 After the iSCSI connection is established, the system boots.

iBFT iSCSI Boot Considerations
When you boot an ESXi host from iSCSI using iBFT-enabled network adapters, certain considerations apply.
The iBFT iSCSI boot does not support the following items:
* IPv6
* Failover for the iBFT-enabled network adapters
NOTE Update your NIC's boot code and iBFT firmware using vendor supplied tools before trying to install and boot VMware ESXi 4.1 release. Consult vendor documentation and VMware HCL guide for supported boot code and iBFT firmware versions for VMware ESXi 4.1 iBFT boot. The boot code and iBFT firmware released by vendors prior to the ESXi 4.1 release might not work.

After you set up your host to boot from iBFT iSCSI, the following restrictions apply:
* You cannot disable the software iSCSI adapter. If the iBFT configuration is present in the BIOS, the host re-enables the software iSCSI adapter during each reboot.
* You cannot remove the iBFT iSCSI boot target using the vSphere Client. The target appears on the list of adapter static targets