What is iBFT?

Hello All...

I have worked on iBFT for more than a year during its initial time. I was surprised to do Software iSCSI during OS boot using this new technology on non iSCSI adapters. Why it is different from normal Software iSCSI? In Normal Software iSCSI, we need a OS installed on which we can install this iSCSI initiator software. In iBFT there is no need of OS to install. It works in preboot environment.

I have performed Native iBFT, System ROM iBFT and using iPXE. I have worked on different scenarios as it was at the initial time. Let me explain this in brief.

We have two different ways to perform an iSCSI configuration.

1. Hardware iSCSI
2. Software iSCSI

In Hardware iSCSI, iSCSI feature is implemented in the Converged Network Adapter and we will be able to perform the iSCSI in Hardware level by using UEFI or Legacy boot methods.

When it comes to Software iSCSI, we will install an application called Software iSCSI initiator which will help in passing the iSCSI parameters.

Briefly, in Hardware iSCSI the adapter will take care of most of work. It will convert SCSI commands to iSCSI CBD while sending requests and converts iSCSI CBDs into SCSI commands. It will take care of the CPU offload, so that less load will be there on CPU. So in Hardware iSCSI, the iSCSI HBA is the one man army.

In software iSCSI, It is all nothing but a software. Here Software will take care of all the work. So To run this software there will be extra load on CPU. The iSCSI initiator software will take care of passing the parameters.

iBFT stands for iSCSI Boot Firmware Table. It provides a standard way to boot from software initiated iSCSI. The iSCSI Boot Firmware (iBF) Table (iBFT) is a block of information that contains various parameters that are useful to the iSCSI Boot process. The iBFT is the mechanism by which iBF parameter values are conveyed to the operating system. The iBF builds and fills in the iBFT. The iBFT is available to the operating system to enable a consistent flow of the boot process.

iBFT can be performed in 3 ways.

1.   Through System ROM

2.      Through Network Adapter Firmware

3.      Through NBP boot program (iPXE)