When you set up a SAN boot device, you use a SAN-attached disk, such as a LUN, as a root device for a host. A SAN boot LUN can be implemented either by an iSCSI HBA or a network interface card (NIC) and software iSCSI stack.
- Software iSCSI
For a software initiator to implement a SAN boot device, you can have the root device on an iSCSI LUN, and you can use any of the following options to load the kernel:
- A host’s locally attached disk (for storing kernel and initrd images)
- A Preboot Execution Environment (PXE) Server
- Hardware iSCSI
If the SAN boot LUN uses an iSCSI HBA, then, because the protocol stack runs on the HBA, it is ready to communicate with the storage system and discover a LUN when it starts up.
You can have both the boot device and root device on an iSCSI LUN.
Note: Not all operating systems supported by the Host Utilities work with iSCSI SAN boot LUNs. For example, Oracle VM does not support creating a SAN boot LUN that uses software iSCSI.